Play A off against B
Definition 1 of 1
Pro Tip 1/3Power Dynamics
This phrase often implies manipulation where one person controls or influences others for personal gain. 
She played her colleagues off against each other to secure the promotion.
Pro Tip 2/3Conflict Creation
Using this phrase suggests deliberate creation of competition or conflict, not occurring naturally. 
He played the two investment firms off against each other to get a better deal.
Pro Tip 3/3Strategic Use
Can imply a strategic or clever use of situations to turn them to one's advantage. 
The negotiator played the bidders off against each other to raise the auction price.