Grand slam champions Dominic Thiem and Stan Wawrinka have both suffered defeats on their long-awaited returns to tennis action at the Andalucia Open.

2020 US Open champion Thiem was making his first appearance since suffering a wrist injury last June while Wawrinka had been absent for more than a year following foot surgery.

Wawrinka, the three-time grand slam winner who turned 37 on Monday, took on Swede Elias Ymer in the second-tier Challenger Tour event and was beaten 6-2 6-4.

He was followed on court by Thiem, who had originally planned to return in Australia in January but decided to put off his comeback until the clay-court season.

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The Austrian was understandably rusty in a 6-3 6-4 defeat by 228th-ranked Argentinian Pedro Cachin.

Thiem, whose ranking has dropped to 50, lost the first five games and, although he improved after that, a break of serve at the start of the second set proved enough for Cachin.