Lion-hearted Alex de Minaur has marched into the quarter-finals of the ATP 500 tournament in Acapulco, dropping just seven games in two matches.
The defending champion made short work of Austrian Sebastian Ofner in their second-round match winning 6-1 6-3, which came after he swept aside Japan's Taro Daniel in their opening match after losing just three games.
The top-ranked Australian's serve proved a deadly weapon on Wednesday night (local time), winning 90 per cent of his first-serve points, but credited his big heart for the victory.
"I've got a very big heart, I'll tell you that," De Minaur said in his post-match interview.
"This heart is going to keep me going, no matter what the score is, where I'm at, what stage of my career I am (in).
"It's what's gotten me to this point so far, and it's what's going to hopefully get me further and further."
The world No.9 also put plenty of pressure on the serve of 37th-ranked Ofner, converting five of 12 break-point opportunities to cruise through after one hour and 29 minutes.
"It's all about trying to put as much pressure as I can on my opponents every single service game," De Minaur said.
"And no matter what the result is in that game, just always try to stay in there and try to win a couple points here and there.
"To be honest, I don't think I'm doing anything special out there. I'm just asking the question."
De Minaur will next play fifth-seeded Greek Stefanos Tsitsipas, who advanced with a 6-3 7-6 (8-6) win over Italian Flavio Cobolli.
In other results, Briton Jack Draper won a battle of lefties against Japan's Yoshihito Nishioka 6-3 6-0 to also move into the last eight.
Dominik Koepfer beat eighth-seeded American Frances Tiafoe 6-4 5-7 6-1, while Miomir Kecmanovic beat Daniel Altmaier 6-4 6-4.
