Second seed Casper Ruud crashed out of the Australian Open second round on Thursday following defeat to hard-hitting American Jenson Brooksby.
A day after Rafael Nadal made an early exit Norwegian Ruud, who took a medical timeout after the second set, succumbed 6-3, 7-5, 6-7, 6-2 to the 39th-ranked Brooksby at Rod Laver Arena.
His early exit left the tournament without its top two seeds after Nadal's loss on the same court on Wednesday to American Mackenzie McDonald. Nadal was later diagnosed with a hip injury and sidelined for up to two months.
Thursday's result potentially opens the door to Novak Djokovic winning a 10th Melbourne title and temporarily derailed Ruud's dreams of becoming world No 1
Brooksby took charge in the first set, breaking twice as the Norwegian hit 15 unforced errors.
Ruud regrouped at the changeover and earned two break points on Brooksby's opening serve in set two, but he failed to convert.
They traded breaks through the second set before the American earned a set point at 5-6 and after a 26-shot rally moved two sets clear on a lucky net cord.
Ruud left the court for a medical timeout at the changeover, apparently for an abdominal problem.
His game didn't improve when he returned, broken two more times before staging a remarkable comeback.
He saved three match points at 3-5 as Brooksby became agitated, before taking it to a tiebreak where he broke early to take it to a fourth set.
Undeterred, the American reset to break Ruud immediately and race to a 3-0 lead.
"First and foremost, Casper is a warrior, I knew it would be a great battle out there," said Brooksby, 22.
"I'm just really proud of my mental resolve after the third-set battle didn't go my way, and to turn it around.
"I thought I was playing really strong and I just didn't want to lose my focus out there."
Ruud said that the pain he felt in his abdominal area midway through the match was due to a long-standing issue that he hoped to address soon.
"It's something that has been with me for around two years since I got a strain here in the fourth round," Ruud said.
"I hope it's nothing serious, but it does come a little bit back here and there, so I need to take care of it and hope I can get rid of it for a long time now."
Meanwhile, there was also a big win for an American woman on Thursday as 21-year-old qualifier Katie Volynets defeated ninth seed Veronika Kudermetova of Russia 6-4, 2-6, 6-2.
“I literally have the chills, because the fans here are just incredible,” said Volynets, who reached the third round of a Grand Slam tournament for the first time. “I’ve never played in a stadium this packed and with that many people keeping the energy up for me. It was awesome.”