By Simon Cambers

NEW YORK (Reuters) - Third seed Stan Wawrinka saved a match point at the U.S. Open on Saturday before squeezing past unheralded Briton Dan Evans in five sets to reach the fourth round. The Swiss faced match point at 5-6 in the fourth-set tiebreak but won it 10-8 and then raced through the final set to clinch a 4-6 6-3 6-7(6) 7-6(8) 6-2 victory. "It was an unbelievable fight," Wawrinka said. "I'm for sure lucky to get through that match, saving match point. He played really great, he's really talented and he was really pushing me. "To finish like that, I'm really happy to get through. It wasn't easy for me to find my best game." World number 64 Evans described his loss as a "heartbreaker" after coming so close to reaching the last 16 of a grand slam for the first time.

Ranked as low as 772 in May of last year, Evans stunned Wawrinka as he took the match to the two-time grand slam champion in a packed Louis Armstrong Stadium. The 26-year-old broke in the 10th game to take the first set and though Wawrinka hit back to level the match, the Briton took the third in a tiebreak. The pair traded breaks at the start of the fourth set but Evans, who surprised Wawrinka with his variety, had match point in the tiebreak as the crowd rose to their feet in anticipation of a massive upset.

But Wawrinka saved it with a volley winner, and that proved the last gasp for Evans as the Swiss, a semi-finalist in New York in two of the past three years, prevailed in the tiebreak and then dominated the fifth set.

"Just a bit of a heartbreaker really," Evans told reporters. "It was a tough one to take. Probably hurt a bit for a while. Disappointing how it sort of played out.

Evans acknowledged that he was felt fatigued after failing to close out the match in the fourth-set tiebreak.

"I was physically pretty tired. Subconsciously, mentally as well. I was hurt a bit. Just one of those things. In the fifth set, he's obviously a class opponent. I sort of knew that was the chance in the fourth set, yeah," the Briton said.

"It's just a difficult one really to sort of take."

Wawrinka, the 2014 Australian Open winner and 2015 French Open champion, will next play Ilya Marchenko of Ukraine.

(Additional reporting by Larry Fine; Editing by Andrew Both)