'Faint' hearted Londero, Mayer looking to halt Nadal, Federer

Unheralded Argentinians Juan Ignacio Londero and Leonardo Mayer stand in the way of Rafael Nadal and Roger Federer in the French Open fourth round, after both put together dream runs at Roland Garros. The 25-year-old Londero is playing in his first Grand Slam main draw after seeing his ranking rise to 78, while it is the 68th-ranked Mayer's 35th appearance in a major. Londero will be facing Nadal for the very first time, but he insisted he won't be cowed despite almost fainting during his five-set third-round win over home hope Corentin Moutet. "I felt that I was going to faint. I don't know if it was the nerves, the sun, that feeling that your legs are loosening," he said, after celebrating his victory by lying flat on his back on the clay. "I'm going to try to win (against Nadal), I'm going to fight like a dog, to play all the points with the intention of winning it. I have to go into it as if it were one more game, from minute one to the last." Londero had previously lost eight times in qualifying for Grand Slams, but has found the tournament proper much more to his liking after breaking into the top 100 thanks to his maiden ATP title in Cordoba in February. He may feel confident, but he is rated a 25/1 shot just to beat Nadal by the bookmakers. The Spanish 11-time French Open champion has only lost twice in his career at Roland Garros -- with 89 wins -- against Robin Soderling in 2009 and Novak Djokovic in 2015. The 32-year-old Mayer could have a better chance of an upset against Federer, as the 20-time Grand Slam title winner is playing the clay-court major for the first time since 2015. But the 37-year-old Swiss is yet to drop a set at Roland Garros this year, while Mayer has battled through in four sets in each of his last two matches. Federer leads the pair's head-to-head 3-0, with Mayer only claiming one set against the third seed -- in Shanghai five years ago. "It's nice, it's a good match, it's a good match for him," said Mayer. "You have to play it. I have to relax now, play my tennis, I want to play that match well. "Playing with Federer is very difficult, because of the way he plays, his talent, his level, everything." Mayer has already matched his best-ever run at a Grand Slam after he reached the Wimbledon fourth round in 2014 before losing to Grigor Dimitrov in straight sets. Londero said he felt faint during his third-round win Mayer has reached the second week of a Grand Slam for only the second time