Pure pain.

Los Angeles Clippers guard Chris Paul took a knee to the groin from Memphis Grizzlies guard O.J. Mayo during the second quarter of Game 3 of a Western Conference first round playoff series at Staples Center.
 
Paul doubled over in pain from the blow, which occurred after a scramble in transition, but was able to continue playing. Grizzlies forward Rudy Gay lost control of the ball on the fast break and both Paul and Mayo crashed to the ground to dig it out. As Mayo got up to chase the play back the other direction, his right knee drove into Paul's groin, causing Paul to flinch instinctively before rolling over in pain.

Paul had been dealing with a groin strain earlier this season but was able to continue playing in Game 3.