The victory continues Vesnina's rise of the a year ago.
At that point, she was two holds from the title. Wawrinka, the highest-ranked player left in the field after the early exits of world number one Andy Murray and number two Novak Djokovic, next faces Spain's Pablo Carreno Busta, a 6-1, 3-6, 7-6 (7/4) victor over Uruguay's Pablo Cuevas. Furthermore, the Russian advanced to the final at the Miami Open a year ago, defeating the three-time defending champion Serena Williams en route but lost to fellow two-time Grand Slam champion Victoria Azarenka in the final, who completed the Sunshine Double.
The 14th seed collapsed to the court with a mixture of ecstasy and exhaustion before the combatants hugged at the net. Vesnina has had considerable success on the doubles circuit with fellow countrywoman Ekaterina Makarova.
The American earned the important second break against a battling Nishikori by converting his fifth break point of a marathon fifth game before going on to serve out victory in one hour 48 minutes.
The duo has reached all four Slam finals in doubles losing in Melbourne in 2014 and Wimbledon in 2015.
"Everything was just so handsome here", Vesnina said. At 31, Kuznetsova, a two-time major champion, is the oldest player left in the women's draw. Kuznetsova still has the desire and hunger for tennis and to achieve more things in her career.
Also consider those wins came in straight sets and that Federer has extra rest entering the semis, and the world No. 10 should have a clear path to the championship.
It was an all-Russian quarterfinal with the eighth seed taking on 19th seed Anastasia Pavlyuchenkova.
Trump, Merkel optimistic trade negotiations can be fair for both sides
Trump was unresponsive when Merkel leaned in for a handshake in the Oval Office at the request of photographers. There was a moment of silence, a confused look from Merkel, and then raucous laughter.
After a dramatic game, Wawrinka managed to eliminate Dominic Thiem from Austria with 2-1 in sets, 6-4 4-6 7-6. Vesnina exploited an errant backhand breaking for 6-5. In the quarterfinals, the Russian was paired with 12th seed Venus Williams. Vesnina now leads their head-to-head 4-2.
It is quite unusual to see Kristina Mladenovic of France reach the quarter-final of a tennis tournament, playing singles.
"When I was up 3-0 in the first set, she was missing some easy shots".
Surprisingly the two Russians have only met on two occasions. Kuznetsova has split two previous matches with Vesnina.
Talking Tennis with Shad and Andrew, a breakdown of the BNP Paribas Finals this Sunday. "She started to put a lot of pressure on me".
"In my opinion, he's the best to ever play".
She said on BT Sport 1: "Today was big and it was electric, I felt the atmosphere and it was a very important match and I was playing pretty good".
Vesnina had never advanced beyond the third round in singles at Indian Wells, although she has won the doubles title at the desert tournament three times. She chats with veterans and former players - picks their brains - anytime she gets a chance.