Europe have won seven of the past nine editions and, with world number one Rory McIlroy leading them at Gleneagles starting Friday, are considered favourites once more.
But Westwood said USA's attempts at playing themselves as underdogs would have no impact.
"I think the teams are very evenly matched. We're maybe slight favourites with regard to we're playing at home," the Englishman said.
"I think whoever has got the advantage becomes slight favourites. But as far as looking at it on paper and matching player for player, it's a very close match.
"I know the Americans are trying to play the underdog role this week. I don't see that really working.
"I don't think there's underdogs and favourites in this. It's just a case of who really holes the putts at the right time, gets the momentum and clings onto that momentum and runs with it as far as possible."
Westwood said putting would be crucial, and playing the final few holes well could be the difference.
"You've got to get it on the green. You've got to hit the ball well," he said.
"If you analyse the European team's performance, we played the last hole probably better over the last few years, and that's probably why, because it's so close, it generally comes down to that.
"That's probably why we've been so successful."