Take a dive
Definition 1 of 3
Pro Tip 1/3Negative Connotation
Using 'take a dive' implies dishonesty or cheating in sports. 
The fans were outraged when they suspected the player had taken a dive.
Pro Tip 2/3Colloquial Use
More common in casual conversation than formal speech. 
Everyone in the bar thought the fighter took a dive.
Pro Tip 3/3Not Literal
It's metaphorical; no actual 'diving' is involved. 
The referee denied any players had taken a dive during the match.