Swiss maestro Roger Federer has a sure-shot chance of becoming world No 1 again, compatriot Stan Wawrinka said. After a six-month layoff caused by a knee injury, Federer has had a stellar 2017 season so far, winning the Australian Open and the Indian Wells Masters.

Federer beat Wawrinka in the semi-finals of the first Grand Slam of the season and then again in the final of Indian Wells earlier this week. Such is Federer’s form that Wawrinka believes he can become the oldest world No 1 in history at the age of 35.

“He’s playing really well, what is different maybe is he is playing closer from the baseline, preferring, using less his slice, he is using more top spin, putting more pressure all the time, returning better that’s the difference I see,” Wawrinka said at the Miami Open. “For sure he has a shot for No 1, he has just won the first Masters final. For sure he has a big shot,” he told reporters.

Andre Agassi holds the record for being the oldest player to hold the men’s No 1 ranking, at the age of 33. “It is going to be interesting to see,” Wawrinka said. Rafa [Nadal] is playing well also and we will see when Novak [Djokovic] and Andy [Murray] are back from injury, it is going to be really interesting for tennis fans.”

Wawrinka said he wasn’t shocked to see Federer back in such good form. “From him nothing is a surprise, but for sure to see him moving that well at that age it is something amazing,” he said. “It is good for me to see that you can be at the top [at that age]. It is amazing to see how he is playing after a six-month injury.”