Cam McEvoy had been having a terrible time waiting for his first swim at the Paris Olympics.

The first Australian man to swim at four Games has blocked out all social media and got a new phone – only his coach, and his partner, have the number.

So McEvoy was bursting to get on the blocks at the Paris La Defense Arena on Thursday morning for his 50m freestyle heat swim.

The 30-year-old says his wait until day six of competition was “terrible”.

“It was honestly almost as hard as the training itself … it is just so boring,” McEvoy said.

The veteran Dolphin topped the heat times with a swift 21.32 seconds.

“I am really happy with the time, I felt really nice,” McEvoy said.

“But three rounds, it’s all about that energy management for this morning and tonight, and then recovery by tomorrow.

“I have just to take it one round at a time.”

Fellow Australian Ben Armbruster (21.86) also advanced to the semi-finals as eighth-quickest in what was also his first swim in Paris – and first at an Olympics.

“It couldn’t come sooner,” Armbruster said.

“I’ve been thinking about this race all week. Just watching my teammates rip in, I was so keen to finally get my suit on and give it my best.”

Also Thursday morning, star Dolphin Kaylee McKeown breezed through her women’s 200m backstroke heats.

The reigning Olympic champion in the event, McKeown (two minutes 08.89 seconds) was third-quickest qualifier for the semi-finals.

McKeown has already successfully defended her 100m backstroke Olympic crown in Paris and is tipped to repeat that feat over the longer distance.

Her compatriot Jaclyn Barclay (2:10.53) missed progressing to the semis by just two-hundredths of a second and was ranked 17th.

Australia’s gold-medal favourites in the women’s 4x200m freestyle relay also booked their berth in the final.

The Australians deployed Lani Pallister, who has recovered from COVID which forced her out of the 1500m event, Jamie Perkins, Brianna Throssell and Shayna Jack.

The quartet were fastest through the heats in 7:45.63 – and they’ll get much faster in the final when summoning big guns Ariarne Titmus and Mollie O’Callaghan.

In the men’s 200m individual medley, fellow Dolphins William Petric (1:58.84, 11th fastest) and Thomas Neill (1:59.13, 14th) both secured semi-final swims.