Toulouse - Australian Caleb Ewan picked up his first Tour de France stage win in a mass sprint at Toulouse on Wednesday as Frenchman Julian Alaphilippe kept the overall lead.

Ewan said at the winning post that victory "almost" made up for leaving his country, his wife and his baby daughter behind to race his first Tour de France.

With defending champion Geraint Thomas and his Ineos team-mate Egan Bernal also finishing in the pack on Wednesday, there was no change in the overall top three after a 167km run from Albi to Toulouse.

Ewan timed his explosive burst to perfection, catching and overtaking Dutch sprinter Dylan Groenewegen right on the line after a long home straight. Elia Viviani was third on a finish designed for the pure sprinters.

"It took me half the Tour de France to get my win, but I got it in the end," said Ewan.

"I let him go, caught his wheel and just had him on the line," explained, the stocky 25-year-old, in his first season with the Lotto-Soudal team.

Ewan insisted the stage win was a dream come true, and emotionally rolled off people to whom he owed his win.

"When I started cycling at 10-years-old, I used to pretend that I was racing in the Tour de France, and winning it," he said.

"Winning this stage almost makes it worthwhile leaving Australia with my wife with our newborn baby daughter, Lee, back home.

"My wife is so strong and I could never have done this without her. She's the one I really have to thank for realising my dream.

Ewan has won stages on all three Grand Tours, with three victories on the Giro this season and one on the Vuelta.

It was a narrow win with the photo-finish, which takes thousands of shots a second from both sides of the finish line, showing a tiny margin of victory.

There are two major mountains on the menu on stage 12 on Thursday with yellow jersey Alaphilippe vowing to defend his lead.

"Geraint Thomas is favourite to win this Tour," insisted Alaphilippe when asked if he could keep the overall lead all the way to Paris.

"He (Thomas) looks so confident, so strong," said Alaphilppe.

"It won't be easy tomorrow, there will be attacks, and it will be a big day on the Tour, but I'm up for it," said the 27-year-old former soldier ahead of the first day in the Pyrenees.

The defending champion and the current leader both enjoyed a geat deal of support on the stage with dozens of Welsh flags almost outnumbering the roadside signs supporting 'Juju' Alaphilippe.

Thomas said he was feeling lucky on Wednesday as the stage left Albi after the rest day.

"I'm on good form thanks, and gaining 1min 40sec on five rivals in the last stage was like a gift," he said of the crosswind-hit run to Albi on Monday which saw a split in the peloton.

"I don't think I ever did that even on a mountain stage," said the 33-year-old.

Sprint points leader Peter Sagan of Slovakia kept his green jersey after finishing fourth behind Ewan.

"I congratulate him, he's too fast for me on that kind of course," said the 30-year-old Sagan.

Colombian Bernal kept hold of the under-25's white jersey and said Ineos would remain calm in their quest for the yellow jersey.

"We won't be attacking just yet, but I feel good going into the mountains," said Bernal, who is on his second Tour.