The Arsenal midfielder has been outstanding this season, leading the assist charts by some distance.
The German star has been in top gear since the beginning of the campaign, with him having been a star man alongside the likes of Alexis Sanchez.
He currently has 11 assists to his name; the most in the Premier League so far, with the nearest competitors only on six.
With a number of Arsenal’s key men now out through injury, he will be needed more than ever as the Gunners look to maintain their faltering title challenge.
Merson, though, says he has already proved to everybody that he is a great player with the displays he has put in.
“Ozil has stepped up and has shown his class,” he told Sky Sports.
“He's taken a lot of stick during his time in England but he is now proving to everybody what a great player he is. He's been outstanding.”
“With Arsenal now without Alexis Sanchez, Ozil is absolutely vital. They cannot afford to lose him to injury. That would be a nightmare.”
The Gunners will be keen to return to winning ways this weekend, with Sunderland travelling to the Emirates.
The Black Cats are 17th in the table at present, but will be buoyed by their win over Stoke City last weekend, their second in succession, the first time they have managed that this season.
In contrast, the Gunners have had two disappointing displays, with the draw at Norwich City following the loss to West Bromwich Albion the week before.
They will be hoping that Ozil can play a big part to try and guide them to three points on Saturday afternoon.