Severin Luthi, ex-coach of Roger Federer, has joked that Stan Wawrinka should 'stop now' following his recent success as his future in tennis stays unclear.

Former world No. 3 Wawrinka has been climbing up the ATP singles rankings again this season, returning to the top 100 by reaching No. 97 in February and re-entering the top 50 in July.

Recently, the 38-year-old emerged victorious alongside compatriot Dominic Stricker in the doubles event at the Swiss Open, lifting the trophy on home soil. Following this, Wawrinka reached the final of the Croatia Open in Umag, ultimately being defeated by Alexei Popyrin in three sets.

In an interview with Blick, Luthi was asked for his thoughts on Wawrinka. Initially, the 47-year-old joked that the player should give up now that he had won the Swiss Open,

"Actually, he should stop now after his double title in Gstaad," he said.

However, he then went on to make it clear that he doesn't want the three-time Grand Slam champion to hang up his racket yet, using his own time as Federer's coach as an example:

"No, seriously, even during the time when Roger was still playing, I was asked again and again whether I was surprised by his successes.

"Now it's exactly the same with Stan, I'm prepared for the surprise because I know how much work he puts into it. Stan lives for this sport, he is always energized, shows incredible passion. It is fascinating.

"If he stays healthy, I definitely believe he can win another title. Wherever. Can he win another Grand Slam tournament? That looks difficult. But here, too, I say, Stan should never be written off. He's proven time and time again what he's capable of. That's always an issue for us in the Davis Cup team," he added.

However, Wawrinka's future in tennis is still unknown, even with his recent successes. Following his frustrating loss in the final at Umag, he broke down in tears:

"I know it’s so stupid to cry," he said, "but I love this sport so much. You make it really special. Amazing week."

He then said that he would 'hopefully' see the crowd there next year, implying that he would like to still be competing in a year's time, but not giving any guarantees just yet:

"Hopefully I can come back. Thank you for the support. Thank you for being here. Hopefully, I see you next year," he said through tears.