Juan Martin del Potro has continued his fine form since returning from injury by beating David Ferrer at the third-round stage of the US Open.
The Rio 2016 silver medallist remains on track to earn his second crown in New York, having eased through 7-6(3) 6-2 6-3 in straight sets.
A three-year injury absence from the game has seen Del Potro plummet down the rankings, but he entered this competition as a wildcard and will now face David Ferrer - who overcome Pablo Carreno-Busta - for a place in the quarter-finals.
Both players lost serve on one occasion in the first set, leading to a tie-break which Del Potro - victorious here in 2009 - took at the third time of asking.
The Argentine held throughout the remaining two sets, breaking his opponent twice in the second and once in the third to comfortably sail through to the fourth round.
