LONDON, June 30, 2016 (Xinhua) -- Roger Federer of Switzerland returns the ball during the men's singles second round match against Marcus Willis of Britain on Day 3 of the 2016 Wimbledon Tennis Championships in London, Britain, on June 29, 2016. Roger Federer won 6-0, 6-3, 6-4. (Xinhua/Han Yan)