Swiss tennis players Roger Federer and Stanislas Wawrinka have both had a good day at Wimbledon, beating Robin Söderling and Juan Martin del Potro respectively.

In a Centre Court shock earlier on Wednesday that could affect Federer, third-seeded Novak Djokovic was beaten in straight sets by Russian former world number one Marat Safin, currently ranked 75. Safin is on course to meet Federer in the semifinals.

Djokovic had earlier claimed Federer was "vulnerable" at this year's Wimbledon.

Five-time champion Federer overcame the world number 41 from Sweden 6-3, 6-4, 7-6 (3). The top-seeded Swiss recovered a break in the third set to secure the straight-sets victory on his second match point in the tiebreak.

Söderling needed treatment for a blister on his left foot during the second set but he did achieve something nobody else has done against Federer on grass this season: he broke the Swiss star's serve.

Thirteenth-seed Wawrinka beat Argentine world number 62 Juan Martin del Potro 7-6 (7:5), 6-3, 7-5 and now faces German world number 92 Mischa Zverev in the third round.

Wawrinka has reached the third round at Wimbledon once before, in 2006, but lost.

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