Djokovic and Nadal face threat as Dominic Thiem joins Stan Wawrinka in injury comeback

Novak Djokovic and Rafael Nadal will face an extra challenge in the upcoming clay-court season with two of their old rivals returning from injury. Three-time Grand Slam champion Stan Wawrinka has already confirmed his participation in next week's Marbella Challenger and now 2020 US Open winner Dominic Thiem will be joining him in his own comeback.

Thiem is the latest former Grand Slam champion to confirm his return from injury. The Austrian was ranked fifth in the world when he hurt his wrist on the grass courts of Mallorca last year and was forced to miss the rest of the season, incluing his first Grand Slam title defence at the US Open.

The 28-year-old has not played since, having to abandon his previous comeback attempts this year in Australia, Cordoba and Indian Wells, and has fallen to No 50 in the world as a result. But there's finally some good news for Thiem, who will be returning in next week's Marbella Challenger ahead of the clay-court season. "I wanted to let you know that I will be playing this upcoming week a tournament in Marbella, Spain. I want to start getting contact with the competition after all these months and I believe this is the right way to start," he wrote on Instagram, announcing his return.

"It's been a very, very tough period for me and to go back to competition is what I need. To step on a tennis court and compete is what I have been waiting for so long and as you know I had a lot of set backs. I know this will be a slow process of getting back to the top level, but I am ready to work hard and start humble."

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The 17-time title-winner joins another former world No 3 making an injury return at the Challenger event in