Spread betting in tennis is the same as handicap betting. That allows bettors to not pick a real match winner, but to do that by giving the less favourite player a handicap (+).
There are two types of spread bets in tennis – games spread and sets spread. Sets spread is straightforward, let’s say you bet on player -1.5 sets, it means 2-0 straight sets victory is required. If you bet +1.5 sets, any won set by an underdog will already result in your victory, too.
There is one main thing that is different from most other sports in tennis games handicap betting. Theoretically, you can even win negative handicap if the player loses. For example three set match of 6-1, 6-7, 6-7 results in player B winning, but it will also mean that player A won 18-15 when we count all the games. Therefore, player A loses the match (and moneyline bets), but would have won even -2.5 spread against player B.