Two-time champion Rafael Nadal raced past third-seeded Marin Cilic 6-1 6-2 to reach the ATP Mexico Open final, where his ideal Acapulco record will be put to the test by Sam Querrey.
Nadal will face American Sam Querrey, a 3-6, 6-1, 7-5 victor over Australia's Nick Kyrgios.
It was the longest tie-break at the main Tour-level event since Frenchman Jo- Wilfried Tsonga won one - also 20-18 - against American Andy Roddick at the 2007 Australian Open.
The final in Acapulco will be the second of Nadal in the year after the Australian Open that he lost to Roger Federer and now he his looking for the 70th title in his career.
Querrey ended Thiem's seven-match winning streak.
Australia's Nick Kyrgios used a barrage of 25 aces to defeat top-seeded Novak Djokovic 7-6 (9), 7-5 early Friday morning and reach the semifinals of the Mexican Open.
"Sam is playing great, beating (David) Goffin and (Dominic) Thiem, so he'll be coming into the match with a lot of confidence", Nadal said.
"Honestly it doesn't change anything when I face them, I simply like to play them", he told reporters when asked about his record. "I believe that he had his chances, but I played a good game".
"I did not play my best tennis, but that's why it has a merit", the Spaniard said.
"He is a big-serving American, I played him before, and I know what to expect", Kyrgios added. The 30-year-old Spanish star overcame a 4-2 deficit in the first set and got out of the 0-2 hole in the second.
The Croatian was supposed to provide the Spaniard with his toughest test yet, after a relatively comfortable draw, but the world No. 6 came through with flyincolorsrs. "I will have to play so much better than today if I want to have a shot".
A medical timeout for courtside treatment on his right elbow seemed to help, and Kyrgios did not face a break point in the third until the final game. I hope to continue like this and we will see at the end of the year.
On the women's side, top-seeded Mirjana Lucic-Baroni of Croatia beat France's Pauline Parmentier 6-2, 6-3.