2013 ALCS Fenway Park
I was at Game 2, Sox had lost game 1 at Fenway so this was a 'must-win'.
Max Scherzer (won Cy Young that year 21-3 record, 0.97 WHIP was DOMINANT) pitched for Tigers. The Sox were shutout in the game 1 loss and looked even more anemic as Scherzer held them hitless thru 5. They scratched across just 1 run in the 7 innings Scherzer pitched and he looked untouchable. We were THRILLED when he didn't come out for the 8th with the Red Sox trailing 5-1.
The Tigers used 2 relievers as the Sox cobbled together an 8th inning rally, eventually loading the bases. My buddy and I had been pounding beers all game and upon the Tigers calling for their 3rd reliever of the inning we raced to the bathroom knowing we had to move quick not to miss Ortiz's coming at-bat.
We got back and stood at our seats just as the first pitch was delivered to Ortiz - he hit a scorching line drive Grand Slam homer that took the Tigers right fielder over the fence with it and had the iconic Boston cop putting his hands up. TIE GAME!
Non-UConn my favorite single moment at a sporting event, and that unquestionably propelled the Sox to win the ALCS (walk-off win in 9th, Ortiz goes on tear rest of postseason) and eventually World Series.