Arsene Wenger feared Danny Welbeck might have lost his edge after 20 months fighting two knee injuries.
Welbeck fired his first goals since April as Arsenal thumped Southampton 5-0 in the FA Cup, with Theo Walcott also scoring a hat-trick at St Mary’s.
Welbeck had only just beaten knee ligament trouble when he suffered cartilage problems in late April, but he flourished on the south coast on Saturday to banish his injury worries.
Gunners boss Wenger hailed the 26-year-old’s resolve in fending off not one but two long-term knee blows to move back towards top form.
Asked if he had feared Welbeck may never recover full sharpness, Wenger said: “You do wonder: I wondered first of all would he be solid enough mentally to cope with that.
“Then secondly you hope he will go well after he comes back after the second surgery.
“He worked very hard, he went through some moments of very deep disappointment. Because when he had the setback and he had to go in again, as a professional player that’s very difficult.
“But he became even more resilient and worked even harder.
“He’s highly respected inside the club because he’s shown so much dedication.
“It was good to see Welbeck be so convincing. I didn’t expect him at that level, because I knew he worked very hard but I didn’t know how much efficiency it would be in a competitive game.
“It was great to see he hasn’t lost his runs or his finishing; it shows as well when you are able to transform that frustration in not playing into efficiency that he’s a special guy.
“There are always two fears, the first is that it takes him too long with decision-making, and second that he would be scared for contact.
“But the runs and also fighting the defenders, it was important for me.”