The semifinal round at the Adelaide International was contested on Friday with the world number one and a sensational teenager reaching the championship match.

Ashleigh Barty rallied to claim a thriller over Danielle Collins while Dayana Yastremska produced another straight sets win, this one over Aryna Sabalenka. The Aussie and the Ukrainian will meet for the title on Saturday afternoon. 

Barty fights back to edge Collins

Barty was under siege early as Collins fired off a series of winners to take a 3-0 lead. She maintained her advantage throughout the set, though she had to dig out of 0-40 in the seventh game and a serve-forehand combination closed out the set one game later. 

The Aussie hit back in the second set, storming through the first five games while improving her serve percentage from 52 in the first to 59 in the second. Collins did well to save two set points, but she missed a backhand at 5-1, 40-15 as the match went to a third set.

Barty survived a spirited challenge by Collins/Photo: AAP
Barty survived a spirited challenge by Collins/Photo: AAP

The decider offered little for the returner, breaks exchanged in the seventh and eighth games the only time either player was taken to deuce. The inevitable tiebreaker began with Collins earning a minibreak only to see Barty hit back for a 4-2 lead.

The American was resilient and saved a match point at 6-4, but an easy backhand miss gave Barty the victory and sent her to a final in the second week of the season for a third consecutive year.

Yastremska continues torrid play, motors past Sabalenka

In the other semifinal, Yastremska rode her serve and massive groundstrokes to a fourth career final and first at Premier level. The teenager took a 3-2 lead in the first set after a wayward backhand by Sabalenka.

Yastremska nearly achieved a double break, leading 5-3, 0-30, but the sixth seed fought back to hold and had her own 0-30 chance only to see the Ukrainian slam down an ace on set point.

Yastremska has not dropped a set en route to the final/Photo: Paul Kane/Getty Images
Yastremska has not dropped a set en route to the final/Photo: Paul Kane/Getty Images

The second set was more of the same as Yastremska bulleted another winner on break point. She was seemingly was on her way to an easy victory until double-faulting three times in the sixth game, handing Sabalenka the break back.

Both ladies held for the rest of the set and a tiebreaker ensued. Winners on both wings gave the 19-year old a 4-1, double minibreak lead. She held two match points at 6-4 and after Sabalenka sent a forehand into the net, the 19-year old advanced to her fourth, and biggest final yet.