With Craig Gordon and Simon Mignolet both out injured, the 27-year-old stepped into the breach following his summer move from Coventry and pulled off a number of good saves in defeat to Manchester United, most notably a double stop from Wayne Rooney and Patrice Evra in the second half.
Westwood told the club's official website: "I want to play. This is my opportunity and I want to take it. Of course you don't want to see someone else injured and Simon's a great lad who I feel for."
The keeper felt Sunderland could count themselves unlucky not to come away with anything from Old Trafford, particularly given the goal was scored by one of their players.
"It was unfortunate but we'll have to take it on the chin I suppose," said Westwood.
"We put in a good performance and were unlucky but we've got to take the positives from it. We kept our shape fantastically and I don't think we deserved to be one down at half-time."