Mertens broke immediately and superbly used her backhand to save a break back chance and extend her lead to 3-0 opening up the court for her second consecutive break.
Kiki Bertens of the Netherlands hits a forehand against Ashley Barty of Australia (not pictured) in the Rogers Cup tennis tournament at Stade IGA. She's playing good tennis.
The 15th-seeded Barty won 80% of her first serve points and broke Bertens four times as she cruised to victory.
Simona Halep marched into the Rogers Cup final with an emphatic straight-sets defeat of Ashleigh Barty.
Halep was not to be denied however, thumping down an ace to seal a memorable win on her next service game.
"I couldn't believe that it's over", said Halep after claiming her third title this year and the 18th of her career.
US Open victor Stephens will go against Halep on Sunday, having only beaten the Romanian twice in their previous eight meetings.
The win put Stephens into the Rogers Cup semifinals for a second year in a row, so she doesn't worry, as some players do, about peaking too soon. In the end Seth Stephens missed two set balls and in the tie-break the American managed to fail, leading 5:1.
World number one Simona Halep triumphed in a re-match of last year's quarter-final against Caroline Garcia to book her spot in the final four at the Rogers Cup. It was the first set Stephens lost all week.
"I was very sore when I woke up", said Halep. I feel like she improved in her mental [side] also. Although she was still working her way back from injury in Washington and Cincinnati a year ago, the manner of the losses in conditions very similar to those in Canada will be a concern for the world #3.
Halap complained Friday about playing the first semifinal day after two straight night matches.
"I never played against her so I don't really know what to expect", said Halep. For sure, I've improved significantly in the last years on changing the surfaces.
"I was very sore when I woke up", she said. "Now, with playing a lot on hard, that has improved". "During the match it's not easy to run so much". In the quarterfinals, she went up against Anastasija Sevastova and won 6-2, 6-2. "I feel like this is where I belong". "I have a few goals that I still want to reach".
"I was really exhausted". "I played very well for a set and a half". "I hope in the future it's going to be better".
- Jury: Roundup Caused California Man's Cancer; Awards $250 Million
- Jose Mourinho Reportedly Confused At Paul Pogba’s ‘Fined’ Comments
- 'Overlooked' Koepka hopes win will bring recognition
- Can Galaxy Note 9 Restore Samsung's Smartphone Business?
- Tiger charges into the hunt as Koepka takes lead at 100th PGA
- Chelsea had £90m bid for Atletico Madrid's Jan Oblak rejected
- Hundreds Injured in Romanian Anticorruption Protests
- Hundreds gather in United States city to oppose white supremacy
- Man arrested following crash into security barriers at Houses of Parliament
- Omarosa’s White House recordings fuel Trump woes