Welbeck, who came through the United academy, played a key role in Brighton's win at Old Trafford on Sunday.
"Welbeck walked out of that tunnel and you could see, shoulders back, chest out, thinking, 'I'm going to terrorise these two'. That's how he played.
"He was a free in the summer because he didn't have a contract. I'd have took him. On today's performance, no doubt."