Dan Biggar "could not care less" if Wales rode their luck to book a place in the World Cup semi-finals.

The Six Nations champions will tackle South Africa in Yokohama on Sunday (kick-off 9am) after edging out France 20-19 in the quarters.

Wales trailed until the 74th minute, but Ross Moriarty's try and a Biggar conversion took the spoils, aided by Sebastien Vahaamahina's red card for elbowing Aaron Wainwright in the face.

"We were pretty terrible in the first 40 minutes," Wales fly-half Biggar said.

"The red card obviously changed the game, there is no doubt about that. We probably got a bit lucky.

"We have to count ourselves a bit lucky, but if you want my honest opinion, I could not care less.

"We are in a World Cup semi-final and have played some good rugby in this tournament so far. Sunday was not one of those days, but a lot of teams wouldn't have the character and desire we have to find a way.

"That's what is important. You get no points for style, no bonus points at this stage of the tournament.

"It's about scoring more points than the opposition, and that is something we did - just about."

It was Wales' 20th victory in their last 23 Tests against all opponents as they delivered another example of digging deep to win a game when backs were against the wall.

And it has left them just 80 minutes away from a possible first World Cup final appearance, where England or New Zealand would await.

"There probably isn't a formula," Biggar added. "What you have got is a group of guys desperate to achieve and who are prepared to dig deep.

"The coaches know they are lucky they have a squad of players here who will dig as deep as anyone in the tournament.

"Looking at the quality of the rugby in the other quarter-finals on Saturday, we were certainly below that, but what we have in abundance and as much as anybody is a desire and a fight not to give in.

"To play South Africa next week we are going to have to be a lot better - there is no getting away from that - and that will be the general theme of the week."

"It's really pleasing that we are here for another two weeks, and hopefully we have two games to potentially change the rest of our lives."