The 2018 Western and Southern Open, one of the final tuneups before the U.S. Open begins Aug. 27, will end this weekend. 

Saturday marks the final four on the men's and women's brackets. The men's semifinals are stacked with talent, as Roger Federer, Marin Cilic, Novak Djokovic and David Goffin look to keep their championship hopes alive. 

The women's semifinals feature No. 1 seed Simona Halep, who's looking to keep her momentum going after winning the Rogers Cup last week. 

Here's how the action from the Lindner Family Tennis Center in Cincinnati, Ohio, played out:

Men's Results

No. 10 Novak Djokovic def. No. 7 Marin Cilic 6-4, 3-6, 6-3

No. 2 Roger Federer def. No. 11 David Goffin 7-6 (3), 1-1 (Retired)

Women's Results

Kiki Bertens def. No. 8 Petra Kvitova 3-6, 6-4, 6-2

No. 1 Simona Halep def. Aryna Sabalenka 6-3, 6-4

Finals Schedule (Sunday, Aug. 19)

Women: No. 1 Simona Halep vs. Kiki Bertens (2 p.m. ET)

Men: No. 2 Roger Federer vs. No. 10 Novak Djokovic (4 p.m. ET)

Full results available via WSOpen.com

No. 2 Roger Federer def. No. 11 David Goffin 7-6 (3), 1-1 (Retired)

Goffin sustained an injury, which forced him to retire in the second set, giving Federer the win and setting up a showdown with Djokovic in the final Sunday. 

Per Tennis World's Andrew Burton, Goffin said he started experiencing pain around his shoulder and elbow during his quarterfinal match against Juan Martin del Potro. 

Goffin took Federer to the limit during the first set, as the No. 2 seed needed a tiebreaker to prevail. Things were even in the second set before the Belgian was unable to continue. 

This marks the second straight match in which Federer has looked vulnerable. He split two tiebreakers in his first two sets against Stan Wawrinka in the quarterfinals before prevailing in the third set. 

One big break for Federer is this match lasted just 62 minutes. By comparison, Djokovic needed 2.5 hours to put away Cilic in their three-set showdown. 

Even though the win wasn't how Federer hoped to get it, it sets up the marquee final matchup. 

Sunday will mark the 46th head-to-head meeting between Federer and Djokovic. Djoker holds a 23-22 advantage in the rivalry, though this will be their first matchup since the 2016 Australian Open semifinals. 

No. 1 Simona Halep def. Aryna Sabalenka 6-3, 6-4

Halep needed just 76 minutes to earn a 6-3, 6-4 straight sets victory over Aryna Sabalenka to set up a meeting with Bertens in Sunday's women's final. 

The women's No. 1 seed hit just one ace in her win, but she was terrific in virtually every other aspect of her game. 

Halep was 60 percent or better in first-serve percentage, first serve percentage won, second service percentage won, break points won and break points saved. 

Despite the loss, Sabalenka's run to the Western and Southern semifinals is a huge step in the right direction. The 20-year-old knocked off three top-15 seeds this week—No. 9 Karolina Pliskova; No. 6 Caroline Garcia; No. 13 Madison Keys—to reach her third semifinal of the season. 

Following her loss, Sabalenka admitted to reporters she was nervous about going up against Halep. 

“I know I was too nervous in the match,” Sabalenka said. “Next time I just want to try to be more calm on the court. I was trying to go for my shots and everything was coming back. I was, like, ‘Why she take everything?’ I was trying to go more harder and harder.

Halep, on the other hand, continues to look like the best player since her surprise third-round exit at Wimbledon. She has won nine straight matches, including six in straight sets.

No. 10 Novak Djokovic def. No. 7 Marin Cilic 6-4, 3-6, 6-3

Djokovic took back control of his head-to-head rivalry with Cilic after his 6-4, 3-6, 6-3 win at the Western and Southern Open on Saturday. 

The win moves Djokovic one step closer to capturing the Golden Masters if he finishes his run in Cincinnati with a title. 

Cilic didn't play badly against his rival. He won many of the statistical categories, including aces (12 to eight), and first- and second-serve percentages (67 to 64). 

Djokovic overcame those numbers by saving nine of his 12 break points and winning 50 percent of his break-point chances (4-of-8). By comparison, Cilic was just 3-of-12 on break points. 

After winning 14 straight matches against Cilic to start his career, Djokovic entered Saturday having dropped the past two matches in their series. This victory moves Djoker to 15-2 in his career against the 2014 U.S. Open champion. 

Djokovic got off to a slow start in 2018 as he rounded into form following the elbow injury he suffered last year. He hit his stride last month at Wimbledon by defeating Kei Nishikori, Rafael Nadal and Kevin Anderson in succession to win his fourth title at the All England Club. 

Now that Djokovic has secured a spot in the Western and Southern Open finals, the rest of the ATP Tour has been put on notice with the year's final Grand Slam event on the horizon. 

Kiki Bertens def. No. 8 Petra Kvitova 3-6, 6-4, 6-2

Despite entering the Western and Southern Open unseeded, Kiki Bertens is playing at the top of her game after a 3-6, 6-4, 6-2 win over No. 8 Petra Kvitova. 

Bertens showed a mixed bag on the serve with 10 aces and seven double-faults, but she excelled at winning 77 percent of her first serves and taking 64 percent of her break-point opportunities. 

It also helped that Kvitova couldn't figure out her serve. The two-time Wimbledon champion had just one ace compared to eight double-faults in defeat. She's also had fits against Bertens lately after losing to the Netherlands native in the third round at the Rogers Cup last week. 

Kvitova looked to be in control after a slow start in the first set. She won the final five games after falling behind 3-1. 

"In the second set I was getting better," Bertens said on the court after her win. "Until the end I felt fit, was going for my shots. My serve was going well in the end. It was just a matter of keeping going, I guess. I think over the last year we practiced a lot, like, to play more aggressive. It's working out well now, so, yeah, I'm really glad with that."

Kvitova once again battled back in the second set after falling behind 3-0, but Bertens course-corrected to earn a 6-4 win heading into the decisive third set. 

Bertens has one singles title this year, which came at the Volvo Car Open in April. She's put together strong runs in her past three tournaments, reaching the quarterfinals at Wimbledon and the Rogers Cup. 

One more win in Ohio will give Bertens more momentum heading into the Connecticut Open next week before heading to New York in search of her first major title.