No. 1 seed Aryna Sabalenka survived a scare from former doubles partner Elise Mertens at the Mutua Madrid Open before advancing past the No. 28 seed to the fourth round 3-6, 6-2, 6-1.

Madrid: Draws | Scores | Order of play

Sabalenka came into the match boasting a hefty 9-2 head-to-head lead over Mertens, including eight in a row dating back to 2018 and a 6-4, 6-1 victory in last week’s Stuttgart quarterfinals. Not only that, but Sabalenka had won 14 consecutive sets against the Belgian — 15 including a 4-0 retirement in 2021. It was a matchup that had not held intrigue for over half a decade.

Their 12th meeting started in much the same vein, with Sabalenka roaring through 10 of the first 11 points. But from 2-0 down, Mertens began to threaten a plot twist, taking six of the next seven games and, for the first time since Zhuhai 2019, a set.

Two-time Madrid champion Sabalenka was swift to resume normal service in the rivalry, though. Turning up the heat and regaining her accuracy, she blew through 12 of the last 15 games of the match to reach the last 16 for the fourth time in her career. She will next face either Peyton Stearns or qualifier Rebeka Masarova.

Keys to the turnaround: “I was trying to find the rhythm on my serve,” Sabalenka said in her on-court interview. “The moment I started focusing on the timing, on not rushing the ball, on not overhitting, things really clicked.”

The stats bore that out. In the first set, she had committed 14 unforced errors. In the second, she reduced that number to five, and in the third to nine. Meanwhile, her winner count rose from seven in the opener to 24 across the next two sets.

Mertens, on the other hand, was increasingly beset by double faults. She had not hit any in the first set, but eight came along in the second and third.