A pumped-up Rafael Nadal qualified for the semifinals of the Qatar Open Thursday, battling to a three-set victory over Andrey Kuznetsov in the match of the tournament so far. Nadal won 6-3, 5-7, 6-4 in just over two hours and was made to work for his victory by the Russian, ranked No. 79 in the world, in a contest which delighted the center court crowd in Doha. A relieved Nadal pumped his fist as he won, showing how much the victory meant to him. "I am very happy to be through, he was playing great," said Nadal immediately afterwards. The Spaniard, looking to recapture the form that has made him a 14-time Grand Slam winner, won the first set comfortably enough but from there the real drama started. Despite initially being a break up, Nadal lost a see-saw second set as Kuznetsov's powerful forehands brought him back into the match. The Russian eventually took it 7-5, the first time the 24-year-old had ever taken a set from Nadal. In their only previous meeting, Nadal, 29, won in three sets at the French Open last year. Then Kuznetsov won only six games on the Paris clay but on a hard court surface Thursday he threatened to cause the biggest upset of the tournament so far. The final set was also unpredictable, with number two seed Nadal again squandering a break advantage before decisively taking the Russian's serve in the ninth game. The world No. 5 then served out immediately afterward to secure a place in the last four where he will play rank outsider Illya Marchenko. The Ukrainian continued his remarkable run, overcoming injury and France's Jeremy Chardy to qualify for the semifinals. The world-ranked No. 94, who knocked defending champion David Ferrer out in the first round, won in straight sets 6-3, 7-6 (7/3). Chardy is ranked No. 31 in the world. Marchenko, 28, triumphed despite calling for two medical timeouts in the second set and receiving treatment on court from a physio for a back problem. "My back didn't work so well tonight," said the Ukrainian. "I hope I am going to be better tomorrow." Marchenko also beat world No. 50 Teymuraz Gabashvili in the second round. Prior to beating Ferrer — the world No. 7 — in three sets Monday, Marchenko had never beaten or taken a set from a top 10-ranked player. Paire enters quarters Local wild card Ramkumar Ramanathan and Italian qualifier Thomas Fabbiano reached their first ATP quarterfinals at the Chennai Open Thursday. Also, third-seeded Benoit Paire of France advanced but sixth-seeded Gilles Muller of Luxembourg was knocked out, by Fabbiano 6-4, 7-5 in the second round. Ramanathan, ranked 248th, won his only previous match on tour at this event two years ago. On Thursday, he defeated Alexander Kudryavtsev of Russia, a lucky loser who replaced injured second seed Kevin Anderson, 3-6, 6-4, 6-4. Ramanathan became the first Indian to reach the Chennai quarters in two years. Paire, last year's ATP comeback player of the year for climbing from out of the top 100 to No. 19, put away Lukas Rosol of the Czech Republic 7-5, 7-5, and Aljaz Bedene of Britain, the runner-up last year, took more than two hours to subdue Luca Vanni of Italy 5-7, 6-3, 6-4.