Dominic Thiem and Pablo Carreno Busta will contest the Rio Open final after their respective wins on Sunday (AEDT).

Thiem, the No.2 seed from Austria, booked his spot in Monday's (AEDT) decider with a straight-set win over Albert Ramos-Vinolas.

Thiem, 23, was a class above as he eased past the No.5 seed 6-1 6-4 on the clay courts in Rio de Janeiro.

Yet to drop a set at the ATP 500 event, Thiem, who hit 21 winners in one hour, 22 minutes on court, will contest his 11th final, having claimed seven titles previously.

Standing in the way of Thiem and an eighth ATP title is No.4 seed Carreno Busta, from Spain.

Carreno Busta ended the fairytale run of wildcard and teenager Casper Ruud in three sets.

Ruud, who could have become the youngest player to reach an ATP singles final since Kei Nishikori in 2008, won the opening set but the 18-year-old faded as Carreno Busta triumphed 2-6 7-5 6-0.

Carreno Busta fended off six break points and converted as many in a semi-final clash lasting just less than two hours.