It turns out the Warriors' backup big man knew just what buttons to push.
Thompson made four 3-pointers during the dramatic fourth, Stephen Curry added a pair of shots from beyond the arc down the stretch and the Golden State Warriors rallied from 27 points down in the second half to beat the Toronto Raptors 112-103 Tuesday night.
Oracle Arena erupted at the final buzzer after being a den of silence for much of the game. Team owner Joe Lacob and general manager Bob Myers ducked into a private room and let out a loud shout while the Warriors celebrated the NBA's biggest comeback this season while jogging off the court.
Afterward, all anyone wanted to talk about was O'Neal's pep talk.
"(He) gave a great speech at halftime," Thompson said. "Honestly, that was what was our turning point. It wasn't in the fourth quarter or the third quarter. It was at halftime."
No one would reveal what O'Neal said.
Golden State's comeback from 18 points down after three quarters was its biggest since storming back from a 19-point deficit to beat the Boston Celtics 126-124 on Feb. 9, 1962.
Warriors coach Mark Jackson, never at a loss for words, could only smile.
"This being my third year here, there has not been a bigger win," Jackson said. "We were not sharp, we were not crisp and we allowed (Toronto) to get it going. To our credit, we began to defend."
Thompson finished with 22 points and seven assists, nearly matching Curry's 27 and 10. David Lee added 18 points and eight rebounds for the Warriors.
Toronto led 75-48 with 9:20 left in the third quarter when Golden State began inching back.
The Warriors trimmed the gap to 88-70 heading into the fourth then stormed back behind an onslaught of 3-pointers.
Golden State made eight 3s over the final 12 minutes, the last coming from Harrison Barnes with 47.2 seconds remaining to give the Warriors a 109-103 lead.
"It's one of those where they started hitting the 3 in the third quarter and we couldn't turn the water off," Toronto coach Dwane Casey said. "We did an excellent job in the first three quarters and then we couldn't score in the fourth quarter."
DeMar DeRozan had 26 points to pace Toronto, which lost its fourth straight. Kyle Lowry added 20 points and nine assists despite being knocked out of the game briefly following a collision with Warriors centre Andrew Bogut.
Golden State was down and nearly out before storming back.
The Raptors scored 65 points in the first half and were scoring almost at will against a Golden State defence that had allowed 100 points or more in six straight games. Toronto made it seven despite scoring just nine points over the final 8:45.
That cold snap opened the door for the Warriors' biggest comeback of the season and extended the Raptors' losing streak in Oakland to nine games.
Curry nearly brought his team back in record-breaking fashion. He made three 3-pointers and needs three more to break Jason Richardson's franchise record of 700.
He got plenty of support in draining 3s.
Thompson went 6 of 12 from beyond the arc, Barnes added two and Draymond Green had one.
"We're shooters," Thompson said. "It just happened to be a night where we were all missing at the same time, and then it turned out we were hitting at the same time."
Barnes finished with 19 points, while O'Neal added 11 points and eight rebounds off the bench.
The Warriors were sloppy on both ends of the court in the first quarter when the Raptors built a 17-point lead.
Rudy Gay and Lowry had seven points apiece as part of a 22-5 run by Toronto. Lowry, who had 11 points in the opening 12 minutes, capped the streak with a buzzer-beating 3-pointer from 26 feet.
Barnes helped Golden State chip away at the lead. He scored nine of the team's first 11 points then added three free throws to pull the Warriors within 48-39.
Toronto's Steve Novak answered with three 3s in 97 seconds, Lowry added a driving layup and Toronto took a 65-48 halftime lead.
The Raptors were still comfortably ahead late in the third quarter when Lowry dropped to the floor after colliding with Bogut. Lowry lay in the key for several moments, then stood up and took a few steps before sitting back down on the court. He was eventually helped to his feet and walked slowly off the court with the help of a pair of Toronto assistants.
Lowry returned with 10:40 left in the fourth quarter — right in the middle of Golden State's best run of the night.
NOTES: Toronto had not scored more than 56 points in any half until its first-half eruption. ... Golden State is 3-0 when O'Neal scores in double figures. ... Raptors' forward Amir Johnson (16 points, 10 rebounds) has double-doubles in each of his past two games against the Warriors.