Chasing an 18th grand slam title, Djokovic was untroubled by Struff in a 6-3 6-3 6-1 win on Arthur Ashe Stadium on Saturday (AEST).

The world No.1 improved to 26-0 in 2020 and he has dropped just one set through his first three rounds in New York.

Djokovic has now made at least the fourth round in his previous 13 appearances at the US Open, where he is a three-time champion.

The Serbian had won all four of his previous meetings with Struff, including twice this year, and he outclassed the No.28 seed from Germany again.

Struff hung in there in the first set, until the eighth game, when Djokovic broke on his way to the opener.

A break in the opening game of the second set put Djokovic further on his way, and he took the Struff serve again to close it out.

Pushed a little to begin the third set, Djokovic landed another break to lead 3-1 and he never looked back on his way to the fourth round.

Awaiting Djokovic in the last 16 is Pablo Carreno Busta, the Spaniard having lost all three of his previous matches against the Serbian.

MATCH STATS

Djokovic [1] bt Struff [28] 6-3 6-3 6-1

WINNERS/UNFORCED ERRORS   

Djokovic – 34/23
Struff – 23/32

ACES/DOUBLE FAULTS   

Djokovic – 4/5
Struff – 8/3

BREAK POINTS WON    

Djokovic – 5/11
Struff – 0/4

FIRST SERVE PERCENTAGE   

Djokovic – 63
Struff – 58

PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE   

Djokovic – 80/57
Struff – 61/44

TOTAL POINTS   

Djokovic – 92
Struff – 64