World number three Sinner will face either Germany's Alexander Zverev or Bulgarian Grigor Dimitrov in Sunday's final and will be a clear favourite after his display of power and skill in the semi-finals.
The Italian had lost to Medvedev in the Miami final last year but beat him in the Australian Open final in January. The outcome was never in doubt this time as Sinner utterly dominated from the outset.
Sinner broke Medvedev's first service game to go 2-0 up in the opening set, pinning the Russian in the corner at the end of a long rally before blasting a winner past him.
While the 22-year-old looked fresh and fired up, blasting with power from the baseline while inventive when he came to the net, Medvedev was struggling to just hold his serve and the Italian broke again in the fourth game, taking advantage of his fourth break point.
A rattled-looking Medvedev finally held in the sixth game but Sinner served out to love to complete a first-set rout in just 33 minutes.
It was the same story in the second set, Sinner breaking to love from the start. The Russian looked dejected after he went wide on a break point to fall to 4-1 down, one of a series of unusually poorly executed shots from the 28-year-old.
Sinner met little resistance on his way to serving out for the match and acknowledged that his emphatic win was helped by the out-of-sorts nature of his opponent's play.
"I felt great on court today. Usually, the more you go on in a tournament, the more comfortable you feel and I'm very happy about today's performance," he said.
"I think Daniel didn't feel this well today. He made a lot of mistakes which he usually doesn't make, so I just took the chance. I was expecting a really tough match."
Sinner has won five straight matches against Medvedev after having lost their first six encounters, the last of which was in the Miami final last year.
Sinner, who enjoyed a run of 19 wins before losing to Carlos Alcaraz in the semi-final at Indian Wells, said he is now a very different proposition than when he missed out in the Miami final.
"I'm a different player, a different person," he said.
"Sometimes, I think back and I remember the night before the final. I couldn't sleep, I was sweating during the night and now I handle the situation much, much better.
"I'm just excited and happy to come back and hopefully I can play some good tennis on Sunday."
