Dominic Thiem reached the last two French Open semifinals but never quite looked like a Grand Slam champion.

This year is different.

The 24-year-old Austrian reached that stage again on Tuesday with a 6-4, 6-2, 6-1 demolition of injured second seed Alexander Zverev and declared himself to be a far superior player to the one who fell in his last two semis.

Novak Djokovic trounced him in straight sets in 2016 and Rafael Nadal again knocked him out in straight sets last year.

With unseeded Italian Marco Cecchinato his opponent on Friday after beating Djokovic, Thiem will be the overwhelming favourite to become the first Austrian since Thomas Muster in 1995 to contest a Grand Slam final.

"I'm a better player in general, for sure," Thiem, the only player to beat possible final opponent Nadal on clay this year, told reporters. "I've improved and developed my game.

"I think this year I'm physically and mentally fresher than I have been the last two years. I know how to handle a Grand Slam now."

Thiem was superb against Kei Nishikori in the fourth round and continued that form against Zverev, bullying the second seed with the weight and accuracy of his groundstrokes.

His serve, too, is a potent weapon these days. He won 79 percent of points on his first serve and 68 percent on his second delivery.

But it is the clinical nature of his matches in Paris that has stood out. Thiem now carries himself like a man not to be meddled with.

"I always knew how to play on clay, but I think that now I'm just making less stupid mistakes," Thiem, who has won more matches on clay this year than 10-times French Open champion Nadal, told reporters.

"Maybe I'm even a little bit more aggressive, and that's a good combination."

He will be wary of Cecchinato, though, after the Italian world number 72 produced a sensational display to down Djokovic.

"Cecchinato is full of confidence, probably the most confident player out there right now," he said.

"He never won a match at a Slam, and now he's in the semifinals. So everything is going easy for him. He can play completely free."