The 27-year-old returned after a four-month absence to bag a brace and help the Black Cats demolish their North East neighbours 5-1 at Heritage Park this afternoon.
Fletcher saw his 2013-14 campaign blighted by injuries as the Scot made only 13 Premier League starts, the last of which came in March.
"It was good to get minutes on the pitch after we've been training for so long," he told the club's official website. "And of course it was nice to get the two goals as well.
"I feel good after it. It was tiring and it felt like it took me a while to get going in the first 10 minutes but I'm happy with that run-out."