Former US Open finalist Greg Rusedski has criticised Novak Djokovic for being too passive at Wimbledon so far.

The defending champion survived a scare against Kevin Anderson in the fourth round as he came back from two sets down to book a quarter-final match with Marin Cilic.

The pair met at the same time last year, with Djokovic edging a five-set match, and Rusedski expects it to be a close game.

He wrote in The Telegraph: "I would not be surprised if Wednesday's match went to five as well, and I am looking for a defending champion's performance from Novak. Thus far, he has not been as aggressive and assertive as we would normally expect.

"Against Kevin Anderson, he was playing conservatively in the first two sets and only turned it on when his back was against the wall.

"I believe that yesterday's win should help him considerably because he came straight on for a one-set shoot-out and finished on a high. Sometimes he needs to be pushed to find his best."

Djokovic is searching for his ninth Grand Slam title, and his third at Wimbledon.