Mertens upsets Kerber to set up Halep Doha decider
The unseeded Elise Mertens will face Simona Halep in the biggest final of her career after knocking Angelique Kerber out of the Qatar Open.
Mertens won three titles last year and will play in her first WTA Premier decider in Doha on Saturday after a 6-4 2-6 6-1 defeat of Kerber.
The world number 21 from Belgium dominated the final set to see off the third seed, who made 36 unforced errors and won only 47 per cent of points behind her first serve.
Mertens struck 29 winners in an inspired display and will be eyeing a third top-10 scalp of the week when she faces Halep, who beat Elina Svitolina in a thriller.
Three-time grand slam champion Kerber failed to grasp two break-point opportunities in the first game of the match and it was first blood to Mertens when she moved into a 3-1 lead.
Kerber got back on serve at 4-3, but winner after winner came off the racket of Mertens and she broke for a second time to take the opening set.
Wimbledon champion Kerber, who won the only previous encounter between the two in the Hopman Cup last year, hit back to level the match after breaking twice in the second.
Kerber was more aggressive in the second set, but became increasingly frustrated as her first serve let her down in the decider and Mertens won five games in a row to march on.