Roger Federer nullified the big serving of Australian Sam Groth to move into the third round of the US Open.
Groth's big claim to fame is having hit a serve of 163mph at a tournament in Korea in 2012, unofficially the fastest serve ever recorded.
The fastest Groth managed on Friday night was 147mph, and he would have known he was in trouble when a delivery of 142mph flew back past him for a clean winner.
Federer generally fares well against big servers and it was no different on Friday night, although the second seed did not have things entirely his own way in a 6-4 6-4 6-4 victory.
It took the Swiss seven games to break Groth's resistance but he looked in total control when he broke again in the opening game of the second set, exploiting the Australian's relative weakness on the volley.
Groth smashed a ball towards the sky-high stands of Arthur Ashe Stadium in frustration, but a game later he was unexpectedly level.
It was no more than a workmanlike performance from Federer but he was always pushing for the opening and forged ahead again to lead 5-4 before taking the set.
Groth had never faced a top-10 player before but he was warming to his task and exploited some sloppy Federer play to break for 4-2 in the third set.
Back came Federer, though, forcing Groth to play a succession of low volleys, and when the Australian double-faulted on break point two games later the writing was on the wall.
Federer served out the victory and then said: "I thought I did pretty well from the start, I created quite a few opportunities. I'm really happy how I played on the return.
"I could maybe have done a bit better on my serve but I thought it was an exciting match. I thought Sam played well and it was tough until the end. He's got unbelievable power. My arm's still shaking a little bit."
The 33-year-old next meets Spaniard Marcel Granollers, who saw off giant Croatian Ivo Karlovic in five sets.
Grigor Dimitrov will attempt to do in the third round what only one player has managed in 28 matches - beat David Goffin.
It is unlikely the Belgian will make the latter stages, but no player arrived in New York with more confidence than Goffin.
After losing to Andy Murray in the first round at Wimbledon, Goffin headed to Scheveningen in Holland to play a Challenger tournament.
He won that, just as he did the next two Challengers he played. Then he played in Kitzbuhel and won that title too - his first on the ATP Tour.
By the time he had come through qualifying in Winston-Salem last week and made the quarter-finals, he had won 25 successive matches.
The run was ended by Jerzy Janowicz, but Goffin remains on a roll and, after beating compatriot Niels Desein in round one, he hammered 32nd seed Joao Sousa 6-4 6-2 6-0 on Friday.
"It's the first time I've won 25 matches in a row and now I'm in the third round for the first time in New York," said Goffin, whose ranking has climbed from 106 to 56 in seven weeks.
"The first tournament I played in Holland, I went there to get some confidence and I had tough matches in the first and second rounds. After that it gave me some confidence.
"I won the first one, second one and then I continued to play well. I won a lot of matches, but it's not over so why not in the next match? I'm very happy with the way I played today. It was a great match."
Goffin faces his stiffest test next in the shape of seventh seed Dimitrov, who trounced Dudi Sela 6-1 6-2 6-2.
"It's a tough match against Grigor," he said. "I have nothing to lose so I'm going to do my best to win this match. It will be an exciting match on a big court so I hope there will be a good atmosphere. I will try to be aggressive like I have been this summer."
Goffin burst into the limelight at the French Open in 2012 when he reached the fourth round as a lucky loser and took a set off Federer.
His upward curve continued for a little while, but a year later Goffin found himself back outside the top 100, the hype taking its toll.
He said: "After that it was tough, but now the French Open is behind me and I'm looking forward. Now the most important thing is this tournament and the next tournaments in the season. I don't care what happened before."
Fourth seed David Ferrer was handed a walkover when opponent Bernard Tomic pulled out with hip problems.
The Australian had surgery on both hips after the Australian Open and did not want to take a risk when he felt pain in the left one following his first-round win over Dustin Brown.
Tomic, who has also been struggling with flu, said: "I don't want to muck around with that area. For sure something is there. I've got to get it checked. It's not good right now. It's painful."
Marin Cilic has been impressive so far, and the 14th seed's 7-6 (7/2) 6-2 6-4 victory over Ilya Marchenko set up a third-round clash with 18th seed Kevin Anderson, who came from a set down to beat Janowicz.
Gael Monfils avoided his customary drama in a 7-5 6-3 6-2 win over Alejandro Gonzalez and next meets fellow Frenchman Richard Gasquet, a 7-6 (7/4) 6-3 6-3 winner over Paolo Lorenzi.
Nineteenth seed Feliciano Lopez won in four sets against Tatsuma Ito.
Sixth seed Tomas Berdych survived a five-set tussle with Martin Klizan to book his place in the third round.
Berdych has struggled for form this summer but avoided becoming the first top-10 seed to go out of the men's tournament, beating the Slovakian 6-3 4-6 6-2 3-6 6-3.
Fifteenth seed Fabio Fognini hit a whopping 64 unforced errors in a 6-3 6-4 6-1 defeat by Frenchman Adrian Mannarino.