The match between Federer and Thiem will have major implications on the battle for a top-four seeding at the French Open.
Federer is currently third in the rankings with Alexander Zverev fourth and Thiem fifth.
Being seeded fifth opens up the possibility of meeting Rafael Nadal or Novak Djokovic in the quarter-finals at Roland Garros and Thiem says he is keen to avoid that.
He said: “A top-four seeding would help for sure. You avoid the biggest names in the quarter-finals.
“It would be nice if it doesn’t happen all the way to the deep rounds. It is very hard and tough. But a top seeding is a good goal yeah.”
ROGER FEDERER VS DOMINIC THIEM LIVE
*Federer 4-1 Thiem
Another routine hold for Federer. Averaging just a minute on his service games. He holds to 15.
Federer 3-1 Thiem*
Federer brings out the SABR (Sneak Attack By Roger) but Thiem stay composed and passes the Swiss, 40-0.
Thiem gets on the board in the first set.
*Federer 3-0 Thiem
Perfect start from the three-time Madrid Open champion as he holds to love.
Federer 2-0 Thiem*
Thiem goes long with forehand, 30-30. But he responds with a forehand down the line. Thiem double fault, deuce.
Break point Federer as Thiem misses again with a forehand. Saved with a lovely forehand winner.
Second break point Federer as Thiem puts a mid-court backhand into the net. And Thiem goes long with a forehand to hand Federer the ideal start.
*Federer 1-0 Thiem
Federer ace to start the match. But Thiem pulls him back to 30-all.
And a backhand winner down the line seals the opening game for Federer.
16:00: The players are out on the court in warm conditions on the Caja Magica.
15:55: Former British No 1 Greg Rusedski is backing Federer to beat Thiem and avoid back-to-back defeats to the world No 5.
“Thiem is the favourite no question about it to win this match,” Rusedski said.
“But I just feel Federer’s got some magic left. Also, this is a match where everybody is saying Thiem should beat Federer.
“Having to deal with expectation, pressure, the altitude where Federer serves well, uses the short slice and has the crowd behind him, it is not going to be so easy for Thiem.
“Federer rarely loses back-to-back-to-back to somebody. Federer’s got a lot of pride, he’s had a lot of preparation and rest.
“Federer got a little tired in the third set against Thiem in Indian Wells. I don’t think Federer is going to be tired today in the third set.
“He’s had perfect preparation coming into Madrid. Thiem is playing absolutely brilliant, was sensational in Barcelona and is doing all the right things.
“But this is Federer. Let’s not forget that. He is considered one of the best of all time and he doesn’t like to lose to anybody.”
15:40: Federer was beaten by Thiem in the Indian Wells final in March and speaking ahead of today’s match the Swiss said he was excited by the prospect of facing the in-form Austrian.
Federer told Tennis Channel: “Thiem has been really crushing it on the clay.
“So I know he is going to be a big test. And he is going to be one of the favourites regardless of what happens for the French Open.
“With Djokovic and Rafa he is right there as one of the top guys so hopefully I can play well and give him some troubles. I’m excited about the match so we’ll see what happens.”
15:25: The winner of this match will play Novak Djokovic in the semis.
Djokovic got through without having to play a match after Marin Cilic withdrew after coming down with food poisoning.
15:00: Hello and welcome to LIVE coverage of Roger Federer’s quarter-final clash against Dominic Thiem at Madrid Open.