Roger Federer and Rafael Nadal remained on track at the US Open as Juan Martin del Potro continued his impressive form.

Federer and Nadal are favoured to meet in the semi-finals in New York, and the duo claimed wins over Feliciano Lopez and Leonardo Mayer respectively on Saturday.

But Del Potro, the 2009 champion at Flushing Meadows, continued his run with a straight-sets victory over Roberto Bautista Agut.

Meanwhile, fellow seeds Dominic Thiem and David Goffin also reached the fourth round.

FINE FEDERER

Federer produced his best performance of this year's US Open in a 6-3 6-3 7-5 victory over Lopez.

The 19-time grand slam champion made it 13 wins from as many matches against Lopez with an impressive display.

Awaiting the Swiss great in the last 16 is Philipp Kohlschreiber after the German beat John Millman 7-5 6-2 6-4.

WASTEFUL NADAL ADVANCES

The world number one squandered his first 13 break-point chances, but eventually settled to beat Mayer 6-7 (3-7) 6-3 6-1 6-4.

Nadal, who was also pushed in the second round, took control after finally converting a break opportunity.

The Spaniard next faces Alexandr Dolgopolov after the Ukrainian crushed Viktor Troicki 6-1 6-0 6-4.

DEL POTRO QUIETLY ADVANCES

Del Potro is a former champion in New York, but his run into the last 16 has been a largely quiet one.

The Argentine 24th seed continued his fine form by easily beating Bautista Agut 6-3 6-3 6-4 – his third consecutive straight-sets win.

Del Potro will meet Thiem in a blockbuster fourth-round clash after the Austrian sixth seed was too good for Adrian Mannarino 7-5 6-3 6-4.

Goffin, the ninth seed, advanced when Gael Monfils retired with the Belgian leading 7-5 5-1, the Frenchman seemingly battling a leg injury.

Also reaching the last 16 was Andrey Rublev, the Russian teenager getting the better of Damir Dzumhur 6-4 6-4 5-7 6-4.