New York:Fourth seed Novak Djokovic reached the US Open semi-finals on Wednesday by outlasting Spain's Fernando Verdasco 7-6 (7/2), 1-6, 7-5, 6-2 in a dour, stamina-sapping encounter.
The Serb will play either top seed and defending champion Roger Federer or Sweden's Robin Soderling for a place in Sunday's final.
"Mentally it was important for me to overcome today's challenge and get into the semi-finals (of a Grand Slam tournament) for the first time in 2009 so I feel a kind of relief," Djokovic said.
"I just hope to continue to play well and challenge Roger Federer if he gets to the semi-final.
"It wasn't a great first set, we both made a lot of unforced errors and I was lucky to get through in the tie-break.
"In the second set I wasn't able to find any rhythm and he deserved to win it, but I managed to come back and that's what matters."
The match was expected to be a bruising, baseline battle and so it started with both men comfortably holding on to serve until the 10th game, when unforced errors from Djokovic set up two break points for the Spaniard.
Two big serves from the Serb, the losing finalist here in 2007, saved those and he then levelled at 5-5.
The ensuing tie-break saw Djokovic gifted an early mini-break thanks to a double fault and he used that to put together five points in a row to take a one set to love lead.
Both players were struggling badly in the gusty, overcast conditions on the Arthur Ashe Stadium court, the proof of which were the 19 unforced errors for Djokovic and 18 for Verdasco in the first set alone.
It got little better at the start of the second set, but Verdasco picked up the pace in the third game and clinched his first break of serve thanks to his trademark forehand drive.
He pulled Djokovic wide on the forehand side with one blow and blasted it past him down the backhand side with another.
That set the tone for a spell of domination from the 25-year-old 10th seed, who made his big breakthrough at the start of the year when he made it into the Australian Open semi-finals and took Nadal all the way before losing in five sets.
Verdasco won the next four games against a static Djokovic to make it six in a row with three consecutive breaks of serve levelling the set scores.
The Spaniard held his serve to open the third set before Djokovic finally stopped the rot by staving off further break points in the following game.
That appeared to jerk the Serb out of his slumber and three games later he secured his first break of serve since the first set to lead 3-2. He gave it right back though in the following game.
Verdasco, who appeared to be in some pain from a stomach muscle strain, saved two break points at 5-5, but he blasted a forehand wide when Djokovic set up a third.
The Serb served out for a two sets to one lead.
Djokovic failed to convert three break points at the start of the second set, but two games later he grabbed the vital, final break he needed with Verdasco struggling more and more with his serve.
The Spaniard took a medical timeout, but there ws no way back for him as Djokovic made it through to the semi-finals for the third straight year.