Murray, Wawrinka in fourth round

While Murray was troubled early by Italian Paolo Lorenzi, the second seed advanced in relatively comfortable fashion. Wawrinka, meanwhile, was on the brink of defeat before advancing in a five-set thriller against Daniel Evans in New York.

Andy Murray celebrates a point in his third round win.

Andy Murray and Stan Wawrinka booked their spots in the fourth round of the US Open, but it was not quite easy sailing for the latter. 

While Murray was troubled early by Italian Paolo Lorenzi, the second seed advanced in relatively comfortable fashion. Wawrinka, meanwhile, was on the brink of defeat before advancing in a five-set thriller against Daniel Evans in New York.  

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There were wins for Juan Martin del Potro, Kei Nishikori, Dominic Thiem and Illya Marchenko on Saturday. 

MURRAY, WAWRINKA ADVANCE

Lorenzi was coming off an almost five-hour battle in the second round, but the Italian provided a difficult proposition for Murray despite his fatigue. 

However, the World No. 2 was too strong for the Italian, with Murray completing a 7-6 (7-4), 5-7, 6-2, 6-3 victory.

Wawrinka had to come from behind against Evans, saving a match point in the fourth set tie-break to complete a 4-6, 6-3, 6-7 (6-8), 7-6 (10-8), 6-2 win. 

Murray faces Grigor Dimitrov next up, who advanced to the fourth round courtesy of a 6-4, 6-1, 3-6, 6-2 triumph over Joao Sousa. 

Swiss third seed Wawrinka will face Marchenko, who won through after Nick Kyrgios retired due to injury after the third set. 

DEL POTRO CONTINUES RUN

Del Potro kept up his stunning form in recent months, with the Rio 2016 silver medallist knocking off 11th seed David Ferrer. 

The Argentinean, making his first appearance at the tournament in three years due to injury, won through to the next round 7-6 (7-3), 6-2, 6-3.

Joining him is Kei Nishikori, who defeated Nicolas Mahut 4-6, 6-1, 6-2, 6-2, while Thiem and Ivo Karlovic also won. 

Thiem recovered from a slow start to see off Pablo Carreno Busta 1-6, 6-4, 6-4, 7-5, while Karlovic defeated American teenager Jared Donaldson 6-4, 7-6 (7-3), 6-3.

MURRAY CONTENT, WAWRINKA'S AGRESSION

"It took me a little bit longer than I would have liked to sort of work things out. But I worked it out, won, got through, and I didn't play good. So I'm happy with that," - Murray on his victory over Lorenzi.

"He was often coming to the net to try to finish the point. I had to play better, to be a little bit more aggressive," - Wawrinka after his battle with Evans. 

FOURTH ROUND BEGINS

The last 16 gets underway with world number one Novak Djokovic taking on Kyle Edmund on Sunday. Rafael Nadal faces Lucas Pouille, Jo-Wilfried Tsonga is up against Jack Sock, and Gael Monfils takes on Marcos Baghdatis.