Portugal Colonial - Sinner survives energy dip, end of streak to see off Machac

Sinner galloped through the first set but slowed in the second, allowing Machac to hit his way back into the match.

"I was struggling a little bit, was a bit tired," Sinner said. "Most important (thing) today was trying to get through somehow.

"I felt great before the match, in the second set I struggled a bit with trying to find the right energy. This can happen. I tried to push myself through which I've done."

Machac squandered two set points on serve at 5-4 in the second but then romped through the tie-break.

That ended Sinner's record streak of 36 straight sets in 1000-level events but he stayed cool to stretch his run of Masters wins to 19.

Even with his opponent struggling, the Czech kept flailing for winners, frequently missing with the court wide open.

He handed Sinner the third-set initiative when wild hitting handed the Italian a break to love in the third game.

Even though Sinner frequently flexed and touched his back during the second set, it was Machac, a right-hander, who called a medical time-out, for treatment to his left arm, while 3-2 down in the third.

Sinner then held serve twice before breaking to love to wrap up victory in two hours and one minute.

"I hope I can recover as much as I can for tomorrow," said the Italian.

His quarter-final opponent, sixth seed Felix Auger-Aliassime, needed to expend less energy to advance. The Canadian was leading Casper Ruud 7-5, 2-2 when the Norwegian retired.

- 'Confident and focused' -

Earlier, 19-year-old Joao Fonseca reached the quarter-finals of a Masters 1000 event for the first time when he strode to a convincing 6-3, 6-2 win over Matteo Berrettini.

Fonseca, who is making his first appearance in Monte Carlo, produced some superb tennis to see off an opponent who had thrashed Daniil Medvedev 6-0, 6-0 in the second round.

The teenager is the youngest man to reach this stage in Monte Carlo since Rafael Nadal and Richard Gasquet in 2005 and is the first Brazilian to reach a Masters quarter-final since Thomaz Bellucci in Madrid in 2011.

He is the second man born in 2006 to reach the quarter-finals at a 1000-level event, after Spaniard Martin Landaluce, who reached the last eight in Miami in March.

"It is super special. I was looking for this result for a long time," Fonseca said on court.

"Of course I want more. I am very confident and focused. I was very happy with the way I fought today. From the beginning, putting a lot of pressure.

"Playing huge return games and very good serve games. I was putting a lot of pressure and that helps you stay more calm during the match."

The Brazilian's last-eight opponent will be world number three Alexander Zverev.

"I think clay is his best surface," Zverev said of Fonseca.

"I am excited to play him for the first time. He is a young upcoming talent and I think we will play each other a lot more in the next couple of years."

Zverev, a two-time semi-finalist at the tournament, despatched Zizou Bergs 6-2, 7-5.

"Still far from the level I played in the US, but this is my first clay tournament," said Zverev.

E.Paulino--PC