Meanwhile, in the men’s tournament, world number one Sinner is through to the Madrid semi-finals for the first time.
The Italian beat 19-year-old home favourite Rafael Jodar 6-2 7-6 (7-0) in just shy of two hours.
He is bidding for his fifth ATP Masters 1000 title in a row, having won in Paris late last year and already secured the Indian Wells, Miami Open and Monte Carlo titles in 2026.
But the four-time Grand Slam champion was made to work in the quarter-final as Madrid-born Jodar showed why there are such high hopes for what he can achieve in the coming years, going toe-to-toe with Sinner in the second set.
“Tough challenge, I knew before the match that he was going to be very tough to beat, especially here, he’s from here and he knows exactly how to play in these conditions,” Sinner told Sky Sports.
Sinner quickly took control, saving a break point when 2-1 down before reeling off five straight games to win the first set.
The second was much more closely contested though, with Jodar earning break points at 3-2 and 4-3. But each time Sinner held firm.
Jodar saved three break points himself to hold and go up 5-4 and held serve again to ensure at least a tiebreak.
But Sinner showed his class, swiftly holding to love before putting on a masterclass in the breaker, winning it without dropping a point.
“I’ve got a little bit more experience and in the second set got a little bit lucky at times with a couple of lines and net cords,” he added.
“But I tried to keep the level as high as I could… I’m happy with how I ended the match.
“[Jodar] is an incredible player. Spain has one more incredible player so it’s great for the sport.”
Sinner will face either France’s Arthur Fils or Jiri Lehecka of Czech Republic in the semi-finals.