Ana Ivanovic was left badly shaken Thursday when an elderly spectator fell on a flight of stairs during her third-round match at the Australian Open, delaying play for almost 30 minutes as she received medical treatment.

The Serbian 20th seed, who eventually beat Latvian qualifier Anastasija Sevastova 6-3, 6-3, said she froze when the sound of the spectator's fall rang through Rod Laver Arena.

"Actually it was -- well, first I felt really bad. I was really shaking, because the sound of the lady falling was really loud. I could hear it," she said of the incident at 4-3 in the first set.

"I stopped immediately. It was really unfortunate, but, I mean, it was the same for both of us."

Tournament officials said the woman "fell on the steps inside Rod Laver Arena" and was helped by a medical professional who happened to be in the crowd before the first-aid team arrived.

As Ivanovic and Sevastova looked on anxiously, an umpire was heard telling them that medics were waiting for a spinal board and collar before they could move the stricken fan.

"The patron was stretchered to the first aid post for observation and further treatment," the officials said, without commenting on her condition.

Ivanovic wished the elderly woman well.

"I just hope the lady was fine. It was actually good that we had to wait a little bit because I was really shaking, because I could imagine and it was not so nice," he said.

"Then they told us she was bleeding, so, yeah, I hope she's well."

The incident comes after Bernard Tomic's match was delayed for 20 minutes on Tuesday while a woman received treatment for an apparent seizure at Hisense Arena.

Like Ivanovic, Tomic was rattled by the incident.

"Potentially, someone's dying and we're not sure what's going on," he said afterwards.

It follows a ball-boy being escorted off court by Carla Suarez earlier this week because he felt faint in the heat, and a ball-girl who was led away by Jo-Wilfried Tsonga after she was dazed by a stray ball.
                  
 'Tough moments'               
                  
When play finally resumed on Thursday, it was Ivanovic dealt with the interruption better, winning the next two games to clinch the opening set.

She got an early break in the second set and held serve before Sevastova, whose best Australian Open performance was the round of 16 in 2011, clawed her way back for 3-3.

But Ivanovic got another crucial break in the eighth game, and a backhand into the net from the Latvian ensured she lived to fight another day.

"I still feel there is room for improvement. That's my challenge every day," the Serb said, who won the French Open in 2008 as a 20-year-old but has never revisited those heights.

"I really try to push myself and to try to get better. There was tough moments in today's match."

Ivanovic, a perennial crowd favourite in Australia, where she has family and once dated golfer Adam Scott, came into the tournament in poor form, crashing at the first hurdle at both the Auckland Classic and Sydney International.

But she has slowly been improving and is in a favourable side of the draw with world number two Simona Halep, whom she could have met in the fourth round, already eliminated.

The win against Sevastova sets up a third-round clash against either 15th-seeded American Madison Keys or Kazakh Yaroslava Shvedova.