WASHINGTON: Defending champion Rafael Nadal survived an epic US Open quarterfinal confrontation to defeat battling ninth seed Dominic Thiem 0-6, 6-4, 7-5, 6-7 (4/7), 7-6 (7/5) and reach the semifinals for the seventh time. However, the 32-year-old was fortunate to triumph on another hot and humid night at Flushing Meadows, 24 hours after Roger Federer had been dumped out of the tournament by John Millman. In a gripping 4-hour 49-minute contest which concluded at 2am, the world No. 1 Nadal won through to keep his bid for a fourth title in New York and 18th Grand Slam crown on track. After suffering a first set ‘bagel’, Nadal had to battle back from breaks in the third and fourth sets before seeing off the first top 20 player he had faced at the US Open since 2013. “I suffered, that’s the right word,” said Nadal after playing his longest ever match at the tournament. “I told myself ‘wake up’,” he said. “I said to Dominic I am sorry. He’s a great guy, a close friend who will have many more opportunities to win the big titles.” Nadal had defeated Thiem in the Roland Garros final in June but this was their first meeting away from a clay court. “He has a great attitude and is a great fighter,” added Nadal. In a dramatic final set, Nadal saw five break points come and go before Thiem went long with a smash on the first match point. It was his 58th unforced error on a night when he sent down 18 aces and fired 74 winners. “It’s going to be stuck in my mind forever. Forever I’m going to remember this match, for sure,” said Thiem after his first ever hard court match against Nadal. “Tennis is cruel sometimes because I think this match didn’t really deserve a loser. But there has to be one.” The semifinal will pit Nadal against third seed and 2009 US Open champion Juan Martin del Potro for the second successive Grand Slam. Meanwhile, in the women’s side of the championship, Serena Williams admitted she was not at her best during her quarterfinal win over Karolina Pliskova. “I was playing really not a good game,” said Williams, who was a point from trailing 4-1 and did fall behind 4-2 while making 22 of her 30 unforced errors in the first set. “I was thinking, ‘You know, I can play better.’ So that was the good news,” she said. “Well, I want to just be able to get past the semis here. It’s been a few, couple, rough semis for me,” Williams said. “But regardless, this has been a great road.”