By SABC Sport
7th June 2024
Zverev, a losing semi-finalist in the previous three years at Roland Garros, triumphed 2-6 6-2 6-4 6-2.
Ruud, the seventh seed from Norway, took the first set very handily, but his level dropped off alarmingly in the second.
At the start of the third it became apparent why as he called for the doctor, who gave him some medication.
In the end it was a comfortable victory for the German fourth seed, who finished the job with an ace after two hours and 35 minutes to set up a final showdown with Carlos Alcaraz on Sunday.
"I've got so much history on this court," said Zverev, who left Philippe Chatrier on crutches two years ago after sustaining a horror ankle injury against Rafael Nadal.
"I've got some of the best and worst memories on this court. I'm in the final after my fourth semi-final and I'm going to give it my all on Sunday."
Aryna Sabalenka struggled with a stomach bug in her quarter-final defeat by teenager Mirra Andreeva on Wednesday and it appeared that two-time runner-up Ruud had suffered the same fate.
"If I waited, you saw how quickly the first set went away," added Zverev.
"Casper is too good a player to wait. I knew I had to be aggressive to take it to him. The balls went in and I'm happy to be in the final.
"Look, I thought the first two sets were very high level, then end of the third I saw he started to move slower.
"His shots were still the same. If I was more passive then he would've won the match. Credit to him for finishing the match. A great champion and a great person."
Zverev's victory came on the day the court case against him for allegedly assaulting his ex-girlfriend was terminated after a settlement was reached.
The 27-year-old was contesting a penalty order and fine of 450,000 euros issued last October.
Zverev had always maintained his innocence and the settlement did not include an admission of guilt.