The Intermarché-Wanty-Gobert cyclist fought off double-digit gradients to record the triumph in 4 hours 32min 39sec following a brutal 175.5-kilometre route from Villaviciosa.

Italian duo Samuele Battistella and Edoardo Zambanini, representing Astana Qazaqstan and Bahrain Victorious respectively, finished 1min 01sec and 1:14 behind the racer winner.

The leading cyclists - which included Meintjes, Belgium's Remco Evenepoel, Spain's Enric Mas and Slovenia's Primož Roglič – battled an average 12.9 per cent gradient climb, and a peak of 24 per cent, in the final 3.9km.

Everyone tried to keep pace with Meintjes but eventually they were forced to relinquish their claim to the stage title.

Meintjes is the second South African to win a stage at the Tour event after Robert Hunter, who won stages in 1999 and 2001.

He said it was "special" to join his compatriot in the history books after the race.

"I've never been on the podium of a World Tour race except for a team classification so that was one of my main goals before stopping my career," the 30-year-old remarked.

"The last few days, I was just not quite fast enough in the mountain finishes to keep up with the general classification guys."

"I was not sure I would still have the best legs.

"I knew it was a really hard climb so it was better to just time trial to the finish."

Quick-Step Alpha Vinyl's Evenepoel missed out on a podium spot by 20sec but his grip on the overall lead strengthened.

This was despite the setback of losing compatriot and teammate Pieter Serry, who tested positive for COVID-19.

Dutch Bahrain Victorious cyclist Wout Poels has also withdrawn after testing for the virus prior to the race and did not start the race, just as was the case for Serry.

Movistar's Mas, who finished eighth, is second in the overall standings and is 1:12 behind Evenepoel.

Jumbo-Visma's Roglič, whose day started off with American teammate Sepp Kuss withdrawing from the Tour with a fever, has dropped 52sec further behind the front runner after coming 10th and is third in the overall event.

Tao Geoghegan Hart suffered a significant setback in keeping pace with Evenepoel after he crashed with under 4km to go.

The British Ineos Grenadiers rider sat fifth prior to the race but has now dropped out of the top 10.

Tomorrow is a scheduled rest day and mass testing for COVID-19 is expected to be conducted.

Stage 10 is planned to take place on Tuesday (August 30) with riders competing in a 31.1km-long individual time trial from Elche to Alicante.