Karolina Pliskova blew her early round US Open struggles away as she produced her most convincing display of the tournament so far to thrash Jennifer Brady and reach the quarter-finals.

Pliskova needed to dig deep against Nicole Gibbs in the second round and had to save a match point against Zhang Shuai last time out, but she was rarely troubled by Brady, cruising to a 6-1 6-0 triumph on Arthur Ashe Stadium.

It was a welcome return to top form for Pliskova, who kept her hopes of remaining world number one alive with the victory.

After Garbine Muguruza's exit at the hands of Petra Kvitova on Sunday, Pliskova must reach the final to guarantee top spot.

On Monday's form, she will be tough to stop as Brady's first appearance in the US Open main draw came to a juddering halt.

Pliskova's shot selection was just too good for her American opponent, deep groundstrokes enabling the Czech to approach the net and execute some deft drop shots and leaving Brady frustrated behind the baseline.

It only took 25 minutes for Pliskova to take the opening set as errors made an unwelcome early appearance in Brady's game.

Eventually the home crowd had something to cheer as Brady got on the board, having lost the first four games of the match, but it was only a brief success as Pliskova fended off two break openings before taking the set.

Stopping the tide proved too difficult for the world number 91 as Pliskova relentlessly raced into the last-eight, subjecting Brady to a bagel in 20 minutes to wrap up victory.

She will likely face a tougher test in the quarters against either Coco Vandeweghe or Lucie Safarova, but Pliskova's confidence should be sky high after such an impressive display.

STATISTICAL BREAKDOWN
Ka Pliskova [1] bt Brady 6-1 6-0

WINNERS/UNFORCED ERRORS
Pliskova - 23/9
Brady - 6/11

ACES/DOUBLE FAULTS
Pliskova - 3/3
Brady - 1/4

BREAK POINTS WON
Pliskova - 6/9
Brady - 0/2

FIRST SERVE PERCENTAGE
Pliskova - 67
Brady - 39

PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Pliskova - 92/42
Brady - 25/36

TOTAL POINTS
Pliskova - 55
Brady - 22