Greece's Ekaterini Stefanidi won the Olympic pole vault on Friday and her country's first athletics gold since the 2004 Athens Games, then defended its integrity after barred Russian Yelena Isinbayeva blasted the event as sub-par without her in the field.

Stefanidi cleared 4.85 metres to beat American Sandi Morris, who took silver.

"Every single athlete in there would have wanted her to be there and have a chance to beat her," Stefanidi said of the two-time Olympic champion, who was excluded from the Rio Games as part of a mass ban on Russian athletes over a doping scandal.

"Things are how they are and we had nothing to do with it."

The competition took place hours after Isinbayeva announced her retirement and said that whoever won would not have earned "a proper gold medal" due to her absence.

Stefanidi, a 26-year-old who lives in the United States, shouted in ecstasy as she cleared the bar at 4.85m and celebrated before she even landed.

"I can't believe what's happened. It's amazing, the crowd were amazing, my parents are here," Stefanidi told reporters. "I'm glad to make my country proud."

Morris, 24, also cleared 4.85 but took silver because of more failed attempts earlier in the competition.

In a show of sportsmanship, she could be seen clapping along with the crowd as Stefanidi prepared for her final, ultimately failed, attempt.

The American also fired back at Isinbayeva's criticism.

"Her comments can be disrespectful and hurtful to the people who were out there tonight," Morris said. "She is someone that I looked up to my entire life and it's kind of disappointing to hear things like that."

New Zealand's Eliza McCartney, 19, cleared 4.80m to tie her national record and take bronze.

American Jennifer Suhr, 34, who won gold in London in 2012 and silver in Beijing in 2008, competed despite fighting illness since arriving in Rio.

She successfully completed only one vault, at 4.60m, after her husband and coach Rick Suhr reported on Twitter on Friday morning that she had woken up "coughing up blood".