Handicap Betting is a bookmaker invention in which a weaker team or side is given a ”head start” or an advantage over a favourite team.
Let us start by saying Barcelona is playing Osasuna. In this match Osasuna is underdog while Barcelona is a favourite to win. Bookmaker will give Osasuna handicap advantage say O-2.
If as a bettor you place handicap bet on Barcelona to win the match and they won by 1-0, then you lose the bet. By handicap interpretation it mean Barcelona lose by 1-2. But if you place handicap bet on Osasuna to win and they lost by 0-1 you won because that would mean Bacelonia 1-2 Osasuna.
From the above example it is known that this kind of betting only applies to the selection you are betting on.