Down one with 13.6 seconds remaining in the extra period, Memphis went to Zach Randolph in isolation in the post. Randolph turned to face Nick Collison before driving baseline, putting up a high-arcing runner over shot-blocking extraordinaire Serge Ibaka. The try rimmed off to the weakside, where Gasol was waiting for the well-timed tip, going over Kevin Durant to get the winning basket with 0.8 seconds remaining.
A long-distance heave at the buzzer by Russell Westbrook sailed well wide, giving the Grizzlies their eighth win in 10 games.
Gasol finished with 14 points (on five-for-12 shooting), 15 rebounds and two blocks. Mike Conley led the way for Memphis with 24 points (on nine-for-21 shooting), seven rebounds, five assists, two steals and a block.
Durant finished with 32 points (on 11-for-28 shooting), eight assists and three rebounds in Oklahoma City's second straight loss. Westbrook added 20 points (on seven-for-25 shooting), four rebounds, three assists and three steals.
Memphis, the West's No. 3 seed, improved to 46-21 with the win. Oklahoma City, the West's No. 2 seed, dropped to 50-19.
It's been a busy week in the NBA for last-second tips, as the Bulls lost on Monday when a potential game-winning Joakim Noah tip was disallowed for offensive basket interference.