play into somebody's hands

play (right) into (one's) hands

To unwittingly do exactly what someone wants or needs in order for their plans or schemes to succeed. Don't waste your time investigating her husband! You're playing into the real killer's hands! These media reports play right into the senator's hands—he just wants something else to distract from the important issues.
See also: hand, play

ˌplay (right) into somebody’s ˈhands

do exactly what an enemy, opponent, etc. wants so that they gain the advantage in a particular situation: The thieves played right into the hands of the law by trying to sell stolen property to a police informer.
See also: hand, play