Nick Kyrgios is hoping injury won't slow his US Open charge after Australia's last man standing surged into the third round with a serving masterclass.
Kyrgios showcased some substance to complement his undoubted style in sweeping past Horacio Zeballos 7-5 6-4 6-4 in one hour and 56 minutes on Thursday night.
Despite battling a painful hip flexor injury, the 14th seed was untouchable on serve, belting 27 aces and not offering his Argentine opponent a solitary break point.
Kyrgios's impressive victory vaulted the 21-year-old into the last 32 of all four grand slam events in a single season for the first time.
He next faces Ukraine's world No.63 Illya Marchenko on Saturday and will be a hot favourite to preserve his proud record of having never lost to an unseeded player in 14 appearances at the majors.
Kyrgios will need some work on his hip before then, though, after requiring a medical timeout and a couple of mid-match massages before seeing off Zeballos.
At one point he complained to his courtside entourage: "I cannot move".
"Yeah, it was obviously bothering me a little bit," Kyrgios said later.
"But I'm doing everything I can for it. I'm getting a lot of physio for it - but my serve sort of got me out of trouble tonight.
"The conditions suit guys with big games, guys that obviously can serve well. These courts favour them a lot."
Kyrgios racked up his 27 aces at an average of almost two a service game and won an extraordinary 45 of 48 points after landing his first delivery.
He also happily fed off six double-faults from Zeballos to break the world No.71 once in each set.
It was more than enough for Kyrgios to be on and off inside two hours and without dropping a set for the second successive match.
"I'm happy I got off quickly," said Kyrgios before reaffirming his big hopes for the last slam of season.
"I'd like to go far. A few big names have gone out, so the draw's opening up a little bit.
"But I'm just taking it one match at a time and not looking too far ahead."
Kyrgios is Australia's last singles hope this year at Flushing Meadows after 2011 women's champion Samantha Stosur crashed to a 6-3 6-3 second-round loss to her Chinese doubles partner Zhang Shaui earlier on Thursday.
HOW THE AUSSIES FARED ON DAY FOUR OF THE US OPEN
Men's singles, second round
14-Nick Kyrgios bt Horacio Zeballos (ARG) 7-5 6-4 6-4
Women's singles, second round
16-Samantha Stosur lost to Zhang Shaui (CHN) 6-3 6-3
