Matteo Arnaldi of Italy returns the ball against Novak Djokovic of Serbia during the Madrid Open tennis tournament in Madrid, Spain. (AP)

MADRID, April 26 (AP): Novak Djokovic cupped his ear to demand more applause from the crowd after the 24-time major winner chased down a lost ball and won an improbable point.

Instead of sparking a comeback, it turned out to be Djokovic's last gasp as he fell in straight sets to Matteo Arnaldi in his first match of the Madrid Open on Saturday.

The 37-year-old Djokovic has lost three matches in a row, including losing the Miami final, and his opener to Alejandro Tabilo at the Monte Carlo Masters two weeks ago, as he struggles at the start of the clay-court swing ahead of the French Open next month.

Arnaldi won 6-3, 6-4, delaying Djokovic’s search for a career 100th title. The Serb was undermined by 32 unforced errors to his opponent's 18 and had his serve broken three times.

It was the first meeting between Djokovic and 44th-ranked Arnaldi of Italy.

"He’s my idol, he’s always been,” Arnaldi said of Djokovic. "To play him at a stage like this was already a victory for me. He’s not at his best right now, so I came on court to try to play my best tennis and win, and it happened.”

Arnaldi raised his arms and turned to the crowd after striking a winner that gave him a second-set break. Djokovic tried to hit right back and had three break points, but Arnaldi rallied to save his serve and finished off the three-time champion.

Djokovic is still seeking his first title of the season after winning his 99th title last August at the Paris Olympics. He has lost four finals since then. The only two players to reach the 100-title milestone are Jimmy Connors (109) and Roger Federer (103).

Arnaldi will next face Damir Dzumhur after he rallied past Sebastian Baez 1-6, 6-1, 6-2.

Russian teenager Mirra Andreeva reached the last 16 for the third straight year by defeating Magdalena Frech 7-5, 6-3.

The 17-year-old Andreeva, ranked No. 7, has yet to lose before the Madrid fourth round.

She reached that stage for the first time in 2023 while playing as a wild card in her second WTA main draw. Last year, her first big quarterfinals came in the Spanish capital.

"I was very, very nervous,” Andreeva said. "I still struggle to find my best tennis in Madrid. Super happy that I could manage to play consistently throughout the whole match.”

Andreeva, who will turn 18 on Tuesday, will next face Ukrainian qualifier Yuliia Starodubtseva, who defeated 18th-seeded Liudmila Samsonova in three sets.