Rafael Nadal maintained his perfect first-round record at the US Open, cruising past John Millman on Tuesday.

The 18-time grand slam champion was untroubled by Australian Millman, easing to a 6-3 6-2 6-2 victory on Arthur Ashe Stadium.

Nadal, a three-time champion at Flushing Meadows, improved to 15-0 in first-round matches in New York.

The Spanish second seed will face another Australian, Thanasi Kokkinakis, in the second round.

After a gruelling start featuring numerous long exchanges, Nadal broke for 3-1 when Millman – trying to be aggressive – sent a forehand long.

Not even a time violation when serving for the set could slow down Nadal, who closed out the opener.

While not at his best, Nadal looked comfortable and he broke in the fifth game of the second set, forcing Millman into an error with a brilliant forehand down the line.

Nadal eased through the second set and made the perfect start to the third, breaking in the opening game after another big forehand.

Millman stunned Roger Federer on his way to the US Open quarter-finals last year, but he was no match for a typically relentless Nadal, who powered through.

STATISTICAL BREAKDOWN
Rafael Nadal [2] bt John Millman 6-3 6-2 6-2

WINNERS/UNFORCED ERRORS
Nadal – 21/31
Millman – 17/22

ACES/DOUBLE FAULTS
Nadal – 6/3
Millman – 4/0

BREAK POINTS WON
Nadal – 5/15
Millman – 0/3

FIRST SERVE PERCENTAGE
Nadal – 58
Millman – 68

PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Nadal – 80/56
Millman – 63/36

TOTAL POINTS
Nadal – 93
Millman – 70