Nishikori battled into his 19th tour-level final, needing one hour and 29 minutes to seal the victory over Wawrinka. Runner-up in Miami (l. to Djokovic) in April, he will appear in his second ATP World Tour Masters 1000 final of the year and third overall.
Nishikori was at his best with his back against the wall in the opening set on Saturday. The Japanese surrendered a quick break in the fourth game, as Wawrinka began pulling away.
But as soon as the Swiss sprinted to a 5-2 advantage, Nishikori stormed back. The third seed would make significant inroads on return, having a break chance in four consecutive Wawrinka service games. With the Swiss serving for the set at 5-3, he would break back, drawing an error with a rifled return.
Four times Wawrinka would find himself on the doorstep of taking the opener, with a pair of set points on Nishikori’s serve at 6-5 and two more in the ensuing tie-break. But the 26-year-old Japanese continued to thrive while under pressure. He reeled off four straight points from 6/4 down in the tie-break and raced to the finish line in the second set, claiming 11 of the last 13 games.
“I think he started much better in the first couple games, especially,” said Nishikori. “He was hitting very good serves and was very aggressive until the 5-3 game. I started returning better and he was missing a little bit. I think he had more chances to get the first set.
“After that, he started playing a little slower. I knew I had to step it up, otherwise he’s going to come back. I’m just happy to win today.”
In total, Nishikori benefited from 37 Wawrinka unforced errors, while striking 17 winners, including eight off his forehand wing. The win halts a 16-match losing streak against Top 5 players and gives him just his second victory over Wawrinka in five FedEx ATP Head2Head encounters.
Nishikori awaits the winner of the second semi-final between three-time champion Novak Djokovic and Frenchman Gael Monfils. He has already faced Djokovic in three Masters 1000 events this year, falling in the Miami final and the Madrid and Rome semis.
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“I think I had a lot of chances in the first set,” said Wawrinka, who was appearing in his first semi-final in his 10th Rogers Cup. “It was a tough match to play Kei today. It was tough conditions, quite windy and fast. I had a lot of opportunities to take the set. I didn’t. In general, the level was up and down from both sides and it was a really tough first set. I should have played better. That’s it.
“It’s a really positive tournament, to make the semi-finals in a Masters 1000 here on hard courts where I never really played well. It’s a good tournament. There is a lot to take from it. After having a good preparation, I think there are many things that I can be happy with.”