Federer finishes with flurry of aces in 3rd round at Miami

Federer, seeded fourth, broke serve early in the second set and finished with 14 aces and 35 winners after struggling in his previous match, when he needed three sets to put away Moldova's Radu Albot. "I must say the a year ago has been unbelievable for him".

Three-time champion Roger Federer had his way with Serb Filip Krajinovic in a 7-5, 6-3 victory.

American Frances Tiafoe battled back to defeat Spain's David Ferrer 5-7 6-3 6-3 to earn his spot in the fourth round, where he will face another defensive specialist, Belgian David Goffin.

He will face either American Reilly Opelka or Russian Daniil Medvedev next.

Krajinovic struggled with injury past year as problems with his ankle, left foot and hand restricted him to just seven tournaments in the first seven months of 2018.

Ferrer, ranked 155th in the world, is on a farewell tour in 2019 having said he'll play a limited number of ATP tournaments.

However, the Swiss battled back to break Albot while leading 6-5 in the second with a backhand volley victor to square the match.

Yet some fierce hitting from the back of the court surprised the predictably pro-Federer crowd and a brilliant run and flick over the net handed him an early break for 3-2.

Halep got the better of Venus and made light work of her to book a place in the quarter-finals with a 6-3, 6-3 win.

He served 13 aces vs. Sousa and next will play Australian Jordan Thompson, who upset No. 24 seed Grigor Dimitrov of Bulgaria 7-5, 7-5.

"Nowadays I feel like "look, I gave it all I had".

Meanwhile, Bianca Andreescu's hopes of extending her 10-match winning streak was brought to an end by injury when the Canadian teenager retired with a shoulder problem while trailing 6-1, 2-0 in her fourth-round clash with Estonia's Anett Kontaveit.

She will meet China's Wang Qiang next.

Kvitova, a two-time Wimbledon champion, is ranked a career-high No. 2 and will rise to No. 1 if she wins the title.