Rampant Nadal is hitting top gear at right time in Big Apple
Rafael Nadal hit form at the US Open to stroll into the quarter-finals for the first time in four years.
The world number one had found the going tough at Flushing Meadows but the hottest day of the tournament so far saw Nadal spark into life.
It took him just an hour and 41 minutes to defeat Ukrainian Alexandr Dolgopolov 6-2 6-4 6-1 and set up a last-eight meeting with Russian teenager Andrey Rublev, who beat David Goffin 7-5, 7-6, 6-3.
The last time Nadal reached this stage in New York, he went on to win his second title, beating Novak Djokovic in the final.
"I think I played a solid match," said the 31-year-old.
"I played with not many mistakes. I know Dolgopolov is a player who can play amazing shots but sometimes he can be a little bit unpredictable
"He combines amazing points with mistakes. I tried to be very focused with my serve and to wait for the opportunities on the return. I'm in the quarter-finals, that's a positive result for me and I'm looking forward to playing better."
Nadal had struggled with his forehand and his return of serve in particular against Taro Daniel and Leonardo Mayer, losing the first set both times.
But those creases had been ironed out and he broke the Dolgopolov serve in the third game.
Most of the attention on the Ukrainian this tournament has been on the scrutiny he is under following match-fixing allegations surrounding a match in Winston-Salem two weeks ago.
But Dolgopolov, who insists he did nothing wrong, has not let that affect him on the court, and this was his first visit to the fourth round of a grand slam in six years.
He went into the clash knowing he had won two of his last three meetings with Nadal but struggled to make any impression on the Spaniard this time.
The second set was more competitive than the first but, once the top seed made the breakthrough, he did not look back.
Meanwhile, Fabio Fognini is ready to accept whatever punishment comes his way for his verbal abuse of an umpire.
The Italian was initially fined 24,000 US dollars (approximately £18,500) after using extremely derogatory language towards Swedish official Louise Engzell during his first-round singles loss.
On Saturday, the Grand Slam Board announced it was investigating whether Fognini had committed a major offence under the Grand Slam Code of Conduct and he was provisionally suspended from the tournament.
As a consequence he and fellow Italian Simone Bolelli were unable to play their third-round doubles match, while he could face further sanctions, including a fine of up to 250,000 dollars (£190,000) and/or a ban from future grand slam events.
Fognini's initial apology on Twitter was hardly effusive but the 30-year-old fully held his hands up and insisted he was not a misogynist.
He said: "I apologise to all. "Not only to the umpire, to whom I apologised already, but to all those who felt hurt, women in the first place. I have nothing against them. Being described as a sexist has hurt me because it's not true."