Roger Federer's sensational form in 2017 shows no signs of abating after he powered past Juan Martin del Potro 6-3 6-4 in the third round of the Miami Open on Tuesday (AEDT).

The Australian Open champion has lost just once so far in the calendar year and was too good for Del Potro in south Florida, the Swiss his usual calm and collected self despite a large Argentine presence in the crowd.

Federer needed just an hour and 23 minutes to seal victory, marking his 16th win in 21 meetings with Del Potro.

He will now meet Roberto Bautista Agut for a place in the quarter-finals as Federer seeks to claim the title in Miami for the first time since 2006.

Some sensational play at the net from Del Potro allowed him to stave off break points in his first service game, but Federer's persistence in keeping up the pressure was eventually rewarded.

Having seen a further two break points go begging, Federer finally pounced on another shaky service game from Del Potro, hitting a fine forehand pass to take a 5-3 lead.

Del Potro responded superbly but could not take advantage of four opportunities to get back on serve in the next game, Federer surviving to win the opener.

The Argentine's defences on serve appeared more solid in the second but he cracked at the first sign of more pressure from Federer, drifting a backhand long to hand the world number six a 3-2 advantage.

Del Potro avoided going two breaks down at 4-2 as he recovered after giving his opponent another opening with a double-fault.

Federer was required to stave off his fifth break point in the subsequent game but he suffered no further scares and emphatically closed out the match by holding to love, a simple forehand on the final point a perfect illustration of the routine nature of his triumph in this latest episode of his impressive renaissance.