Italian qualifier Sara Errani battled her way to a grueling 3-6, 7-5, 7-5 victory over former World No.1 Caroline Wozniacki of Denmark in the opening round of the Mutua Madrid Open on Wednesday.

In the clash between former Top 5 players, Errani took 2 hours and 48 minutes to fight back from a set down and overcome Wozniacki, who reached the Madrid final in its inaugural edition as a WTA 1000 event in 2009.

Next up: Errani, a Madrid semifinalist in 2013, advances into the second round, where she will face No.11 seed Beatriz Haddad Maia of Brazil.

Errani leads Haddad Maia 3-1 in their head-to-head, with one of the Italian's wins coming in Madrid qualies in 2018. However, that was their most recent meeting, which was well before Haddad Maia's surge into the Top 20.

Italian renaissance: 36-year-old Errani has demonstrated exceptional clay-court prowess over her lengthy career. She has the most tour-level clay-court match-wins of any active player with 194; Venus Williams is second place with 167. (Wozniacki ranks sixth with 109.)

Errani, the 2012 Roland Garros runner-up, is still hanging onto a Top 100 spot at exactly World No.100. The Italian has pulled off a strong clay-court stretch already this spring.

In Bogota at the start of this month, Errani moved into her first WTA-level semifinal since 2017, picking up three wins before losing to eventual champion Camila Osorio.

Errani also qualified for main draws last week in Stuttgart and this week in Madrid, and she has now won eight of her 10 clay-court matches at all levels this year.

Red (clay) alert: Still in the midst of her comeback from a three-year maternity leave, Wozniacki came close to earning her first win on red clay in nearly six years.

The Dane's last match-win on red clay came over Pauline Parmentier in the third round of 2018 Roland Garros. Since then, Wozniacki has won green-clay matches in Charleston in 2019 as well as this year, but she has gone 0-4 in her last four red-clay matches.

Mateo Villalba/Mutua Madrid Open

Tale of the match: Wozniacki stormed through the first set, where she had 16 winners to Errani's five. But the second set was a different story, where Errani slammed backhand winners to break Wozniacki at both 4-4 and 5-5.

Errani missed out on three consecutive set points at 5-4, getting broken from 40-0 up. However, at 6-5, the Italian converted her fourth set point to level the match.

In the decider, the pair traded breaks three times en route to 5-5, but Errani found another winning backhand to earn her fourth break of the set and lead 6-5. This time, Errani served out the match, collecting just her second win in six career meetings with Wozniacki.