Medvedev has won 19 of his 20 titles, including the 2021 U.S. Open, on hard courts, with a grass court crown that same year at the Mallorca Open. He won his lone clay court trophy at the 2023 Rome Masters in the lead-up to Roland Garros.
Medvedev, who was runner-up at the Australian Open in January, did not have a great start to the clay court season after losing early in Monte Carlo this month.
However, he said he could see improvements in his game under Simon, who won five tour-level trophies on clay.
"He tries to bring something to my game, which maybe I thought of, but didn't understand how I should bring it on the court," Medvedev told reporters at the Madrid Open.
"He explains how I can do it and for me then it's important because during the match you don't have time to think too much. It's more of a reaction. So I have to be smart to not overthink what he says. Overthink it in practice, maybe, but not during the match.
"I feel like in Monte Carlo, because we talked a lot about playing ... I maybe thought too much about 'OK, next shot, what do I do?' Where I actually had to play more.
"It's very interesting and for the moment it's working great. I'm looking forward to learning more things."
Medvedev begins his Madrid campaign against Christopher O'Connell or Matteo Arnaldi.
