The English golfer represented Europe in 11 Ryder Cups between 1997 and 2021 and explained that he struggled to comprehend the team's famous comeback from 10-6 down on US soil, even when watching it back afterwards.
Westwood told Golf Monthly magazine: "I've played in 11, and whether it's been the seven winning sides or the four losing ones, there have been great memories from every one.
"From playing at Valderrama, with Seve Ballesteros as my captain and Nick Faldo as my partner, to the last one there at Whistling Straits during Covid, with no away fans allowed and taking a bit of a beating, there have been great moments to pick out of all of them.
"But there will be no day greater than the final day at Medinah in 2012, when we came back from I think it was four points down there.
"I watched a video afterwards when I got home, and even though I knew we won with an hour to go, I thought, how the hell have we won this? I still didn't believe it. Every single card fell in our favour."
Westwood revealed that Darren Clarke and Sergio Garcia were his favourite playing partners at the Ryder Cup and explained how he relished the unique team format of the event.
The former world number one said: "I had a lot of good partners. Myself and Darren Clarke have a great record and myself and Sergio also have a great record.
"I've always been good at picking partners and I think it's part of the fun of team golf – not just representing yourself, but trying to win points for your team and your teammates."
Westwood revealed that players have a "big say" in who their partners will be at the Ryder Cup.
He explained: "You have a big say. I mean, it does depend on the captain, but you do have a big say. You go to the captain and say, 'I'd like to play with...' and you give three names or something like that, and hopefully you get one of those.
"But I have played with people when I didn't give their name and where they didn't appear to be a suitable partner for the way I played golf."