Team strength as the main predictor.

[Natalim]

-snip-
Not entirely true, a strong opponent can be beaten by a weaker opponent if they implement a counter strategy.  After all team sports is a game of strategy, being strong alone won't get the team that far if they get too cocky and without a proper strategic plan from the coach.

Being too arrogant may be the real cause because some sports clubs with big names sometimes underestimate the strength of clubs that are below their average.
Then feel strong and careless in attacking and strategizing, it will be the cause of a strong club's defeat.

And also it depends on luck and making the best use of opportunities at the club that is underestimated.
Team strength and cohesiveness in setting strategies and counter-attacking will be a deadly secret weapon.

Not only that, while a team keeps winning, they become so popular that bettors believe they can't lose. That's where the bookmakers come into play by creating overvalued lines on the favorites. Because the public bets on the favorite, they are likely to lose due to the overvalued line. There's a point spread in the game, and more than 50% of bettors focus on this. Even if the favorites win, if they fail to cover the spread, the bettors will lose their bets. That's how it works.

[wxa7115]

Not only that, while a team keeps winning, they become so popular that bettors believe they can't lose. That's where the bookmakers come into play by creating overvalued lines on the favorites. Because the public bets on the favorite, they are likely to lose due to the overvalued line. There's a point spread in the game, and more than 50% of bettors focus on this. Even if the favorites win, if they fail to cover the spread, the bettors will lose their bets. That's how it works.

This can be a great opportunity for the gamblers that actually know what they are doing, as they can notice those kind of lines, avoid taking them and instead take a bet against those teams.

This can be a great move, because as casinos take so many bets for those powerful teams, they may try to encourage other gamblers to take the other side by offering slightly better odds in order to balance their books, and that is when a smart gambler can get odds so favorable that it may have been impossible to get otherwise.

[crwth]

I think it's always going to be the case because you can really see how it will dominate the opponent if you are going to see the match. It's like playing games and you have those statistics that you can see, then you will know who has the advantage.

If you are really looking for great wins, I think you can win by betting on the underdogs that you know could probably turn around the game. This kind of bet is really risky but it happens sometimes.

Imagine the recent Euro 2024, where Germany lost on the stage games. It's just really surprising you know? Human reactions are not always predictable.

[Kelward]

Sports bet is not like most casino games that depends totally on luck, it requires some levels of analysis because it's fellow human beings with strengths and weaknesses that are involved. Team strength is a major factor that I consider before a bet, a strong team with lots of world class experienced players has a better chance of winning a match than an average team. If some of the experienced players will not feature in a match, then you can start to restrategize their chances of winning in the match. As the OP pointed out, if it's two teams that you think that they have equal ratings, then you can consider home advantage, but that doesn't guarantee that the home team will win.

[Julien_Olynpic]

-snip-
Not entirely true, a strong opponent can be beaten by a weaker opponent if they implement a counter strategy.  After all team sports is a game of strategy, being strong alone won't get the team that far if they get too cocky and without a proper strategic plan from the coach.

Being too arrogant may be the real cause because some sports clubs with big names sometimes underestimate the strength of clubs that are below their average.
Then feel strong and careless in attacking and strategizing, it will be the cause of a strong club's defeat.

And also it depends on luck and making the best use of opportunities at the club that is underestimated.
Team strength and cohesiveness in setting strategies and counter-attacking will be a deadly secret weapon.

Not only that, while a team keeps winning, they become so popular that bettors believe they can't lose. That's where the bookmakers come into play by creating overvalued lines on the favorites. Because the public bets on the favorite, they are likely to lose due to the overvalued line. There's a point spread in the game, and more than 50% of bettors focus on this. Even if the favorites win, if they fail to cover the spread, the bettors will lose their bets. That's how it works.

This is a very important note. Indeed, sports betting is structured in such a way that it is not enough for us to correctly predict the outcome of the match. It is important for us to be more right than the bookmaker. And to do this, we need to understand where the bookmaker can make mistakes. The bookmaker may incorrectly set the odds for the game. You can argue otherwise, but since sometimes players win big bets, it is obvious that the bookmaker was wrong.

[Adbitco]

Most times change of players like buying and signing new players to the team could be a criteria to determine how the small team could beat the bigger team. For instance let say if two teams meet for this season and it happens that the bigger team beat the small team, maybe their meeting is another 2 years or 3 years time at this point the smaller team may reformed and get newer player signed in to their clubs and if it happens they are good then there's every possibilities for the small team to beat the bigger team in their next return meeting.

[Strongkored]

I know that many experienced sports bettors place the greatest importance on the strength of teams (in team sports) or the strength of individual players (in individual sports). They believe that this is what plays a decisive role, and not other factors. For example, the advantage of home games only appears in competition between approximately equal teams. And when teams or players are not equal in strength, then comparing the strength of the teams becomes of primary importance. You may also cite other factors, such as:
1. Coach.

I don't think the coach will be one of the things to consider when making predictions, the role of the coach is important because he is the strategist, but that is included in the team's strengths, so if the coach is bad it is very clear that the team will not be a strong team and vice versa.

3. Player injuries.

This can be a consideration because it will clearly affect the performance for group and also individual sports, but I mostly just look at Head To Head, but this is not always a consideration that will make our betting predictions correct, this is just an option.

Some other sport-specific factors. For example, for tennis, the surface on which the game is played matters - artificial or natural.

In tennis, it is true that the surface is very influential because you can see that there are players who can win on certain surfaces many times, it is even like a certainty that they will win, but they will be just average players on different surfaces, but there are also players who are very good on all surfaces, but that's not much.

The strength of teams or players is usually expressed in rankings.
What do you think: is the strength of teams or players the main factor in the forecast or not? Is ranking the only way to determine the strength of teams? And if these are the main factors, then how can you predict in advance the outcome of a game in which outsiders beat experienced teams?

The strength of the team can be a consideration, but sometimes bettors can choose different things when they see a decreasing factor in the strong team, ranking is not the only thing that determines a strong team, there are definitely other factors such as host factors and even tournament factors. You can see which teams looks bad in the league as Sevilla will be very strong in the European League final and have not even been beaten in the finals.

[Promocodeudo]

I know that many experienced sports bettors place the greatest importance on the strength of teams (in team sports) or the strength of individual players (in individual sports). They believe that this is what plays a decisive role, and not other factors. For example, the advantage of home games only appears in competition between approximately equal teams. And when teams or players are not equal in strength, then comparing the strength of the teams becomes of primary importance. You may also cite other factors, such as:
1. Coach.
2. Judging.
3. Player injuries.
4. Season of the year.
Some other sport-specific factors. For example, for tennis, the surface on which the game is played matters - artificial or natural.
 The strength of teams or players is usually expressed in rankings.
What do you think: is the strength of teams or players the main factor in the forecast or not? Is ranking the only way to determine the strength of teams? And if these are the main factors, then how can you predict in advance the outcome of a game in which outsiders beat experienced teams?

Although fixture matters but another thing is that we don't expect a team in good form to constantly win because things changes and the day this change will come know one knows, some factors to consider when an underated team beat an overrated team is the occurrence that took place in the match, sometimes an overated team with good players may have 2 man down because of red card, this may cause difficulty for the team to able to efficiently hold their defense in other not to allow their opponent to get a good, lets not forget that in the absence of 2 players in a team, if such team excapes wining then we can attribute it to luck because it is not easy for incomplete team to withstand a complete team with their players intact.

When predicting the possible future of a match in which outsider beats an experienced team as you said, we should check the visiting team performance in their away matches irrespective of whom they are meeting with and the current form of the visiting team with the aforementioned we can take our stands but sincerely I must say that this kind of prediction is very difficult.