Serena Williams vs. Kiki Bertens: Score and Reaction from 2016 French Open

Serena Williams will compete in her fourth French Open final after she defeated the unseeded Kiki Bertens in straight sets on Friday at Roland Garros.

The American emerged triumphant in an epic tiebreaker in the first set before coming from a break down to take the second, winning 7-6(7), 6-4.

As in her performance on Thursday—and indeed much of last year's tournament as she struggled for form and fitness—Williams was well below her usual standard but progressed thanks to her indomitable resilience and clinical play.

The world No. 1 endured a poor start to the match as she double-faulted to gift Bertens a break in the first game.

Bertens then held her serve in style:

At 3-1, she had an excellent chance to go two breaks up, but a pair of loose misses cost her the opportunity—as did a forehand into the net on set point at 5-3.

Williams had looked lethargic in the early stages, but that did not stop her from clawing her way back into the contest.

Ben Rothenberg of the New York Times noted the 34-year-old was not playing her usual game:

Nevertheless, she was able to force a tiebreaker, in which they continued to prove evenly matched. Both could only find the net as they each enjoyed a set point, but Williams was eventually able to draw first blood with a volley.

The New York Times' Christopher Clarey lauded her remarkable ability to grind out wins even when not at her best:

Bertens once again broke early in the second set, but this time Williams was much quicker to offer a reply as she broke back to reach 2-2.

PHILIPPE LOPEZ/Getty Images

The 24-year-old almost grabbed another vital break soon after, but despite two break points, she once again couldn't finish off her opponent. Williams punished her in the following game with a vicious forehand to go 4-3 up.

At 5-3, Bertens showed tremendous spirit—as she did throughout—to save three match points, but she could only delay the inevitable. A long forehand in the following game gave Williams the win.

The 21-time Grand Slam winner will face Garbine Muguruza in the final after she made short work of Samantha Stosur.

Williams leads their head-to-head record 3-1, but in the pair's only meeting at the French Open, it was the Spaniard who triumphed 6-2, 6-2 to stun her in the second round in 2014. If Williams affords Muguruza the same opportunities that she did Bertens, she may find herself on the losing end once again.