WATCH the Madrid Open LIVE in Australia on beIN SPORTS | Subscribe here and take advantage of our 7-day FREE TRIAL

Fritz has been nursing an abdominal injury since February, which has kept him out of the game since his semi-final run at Miami last month.

But the American looked in sharp form on his return, playing in his first clay-court match since the Paris 2024 Olympic Games and easily dealing with O'Connell's challenge.

“It feels great to come back and play a really solid match,” Fritz said.

“I didn’t want to jinx it before the match, but I was telling my coach that I was really impressed with how my level has been in practice the last couple of days.

“The first ball I hit since the match I lost in Miami was the day before I flew here, so I had three weeks of nothing, then five days of tennis. I’m super happy I can come out and produce that level on the little bit of prep I had.”

Fritz has a 15-6 record in 2025, and will face Benjamin Bonzi in the next round after he upset No.27 seed Hubert Hurkacz 6-4 7-5.

Fritz reached the semi-finals in the Spanish capital last year before falling to eventual champion Andrey Rublev.

Alexei Popyrin was another Australian in action, but he too suffered a defeat, losing 4-6 6-7 (4-7) to Alexander Bublik.

Alex de Minaur, the No.6 seed and Australia's best hope of victory in Madrid, has a tricky first match against Lorenzo Sonego, whom he will play from 8:10pm on Saturday night (AEST).