Roger Federer vs. Stan Wawrinka: Score, Reaction from 2015 ATP World Tour Finals

Roger Federer continued his dominance over Swiss countryman Stan Wawrinka Saturday with a 7-5, 6-3 victory in the semifinals of the ATP World Tour Finals in London.

The third-seeded Fed improved his career record to 18-3 against No. 4 Wawrinka, and he booked a spot in the final against No. 1 Novak Djokovic, who beat Rafael Nadal earlier in the day.

Although the night ended in disappointment for Wawrinka, he showed his respect for his former Olympic gold medal-winning doubles partner in defeat, per Tennis Now on Twitter:

Federer and Wawrinka met in the semifinals of the same tournament last year, and while the result was the same with the 17-time Grand Slam champion coming out on top, the route there was far different.

Wawrinka pushed Federer to a third-set tiebreak in 2014 before ultimately losing. His performance in that encounter coupled with his strong run this year seemed to give him some confidence entering Saturday's match, according to ATPWorldTour.com:

"

It's an amazing tournament to play. It's a big chance to be in the top eight at the end of the year. I always try to enjoy it. I always try to give everything. The conditions are normally quite good for me. But you also play only the top eight guys. If you look at the last two years, almost two and a half, I started to beat a lot of the top guys. I started to be really confident against them, that I have the game to beat them.

"

The two-time Grand Slam titlist's fine form was on display early as he earned a quick break against Federer, but his veteran opponent was able to bounce back and put things back on equal footing.

Wawrinka had an opportunity to force a tiebreak with Federer leading 6-5, but he made a critical error that cost him the opening set, per freelance tennis writer Carole Bouchard:

"

Why would u rush to net on Federer’s FH? Twice? Stan goes masochist, and Roger breaks 7-5. We need Mirka to make this match interesting now

— Carole Bouchard (@carole_bouchard) November 21, 2015"

Sky Sports Tennis provided a look at the passing shot that essentially sealed Wawrinka's fate in the opening set:

While the first set was tightly contested, the same couldn't be said for the second as Federer rushed out to a 3-0 lead. Wawrinka stopped the bleeding by finally holding serve, but the damage had already been done.

Federer closed the second set out at 6-3 to end the match, and the fact that Wawrinka essentially went out with a whimper surprised Jon Wertheim of Sports Illustrated to some degree:

There is no question that Wawrinka has enjoyed a spectacular year, as evidenced by his French Open triumph—which saw him beat both Federer and Djokovic. With that said, Fed versus Djoker remains the big-money match in men's tennis.

Federer and Nole have combined to win each of the past five ATP World Tour Finals, with Djokovic taking the past three. Fed is a six-time winner of the event, though, and he has looked better in 2015 than he has in quite some time despite the lack of a Grand Slam title.

Entering Sunday's final, Federer holds a 22-21 advantage over Djokovic all time, including a 7-5, 6-2 victory over Djoker in round-robin play earlier in this event.

Another win over Djokovic Sunday won't add to Federer's Grand Slam total, but it could give him a huge momentum boost heading toward the 2016 Australian Open.

Follow @MikeChiari on Twitter.