The 22-year-old Russian lost to Nikoloz Basilashvili in last year's final and will look to go one better after battling past Casper Ruud in the semi-finals on Sunday (AEST).

Rublev, aiming for a third title of 2020 and fifth of his burgeoning career, outfought Ruud on the way to a 6-4 6-2 win at the clay-court event.

"The match was really tough. I think everyone saw how tough it was, how [many] long rallies we had, how many chances both of us had," Rublev said.

He added: "It could [have been] easily 6-4, 6-2 to Casper’s side, but I was a little bit lucky. In the most important moments and at the end, the match was for me. I am really happy with the way I played today."

Rublev fell in the second round in Rome last week, following a run to the US Open quarter-finals, and his form has been inconsistent this year, yet sporadically brilliant.

Titles came in Qatar and Adelaide at the start of the year, and now another beckons in Germany.

The No.5 seed said: "[It is] my first ever time that two years in a row I reached a final at the same tournament. For the moment, it is the most special tournament for me. We will see how it goes [on Monday AEST]."

Tsitsipas, the No.2 seed, halted Chilean Cristian Garin in a three-set thriller he described as "nerve-wracking".

The Greek will chase a second title of 2020 on Monday (AEST), before joining Rublev in heading to the French Open.

A 7-5 3-6 6-4 success against Garin sent the world No.6 through to a 12th career ATP final, battle-hardened for the clash with Rublev.

The French Open also begins on Sunday, but Tsitsipas and Rublev are not due to begin their challenges in Paris on the opening day of the grand slam.