Vesnina was the first to move through, clinching a lengthy 57-minute opening set then storming out to a 4-1 lead in the second set and never really looking back to beat the No.2-seeded Li Na, 76(4) 63.
"I always enjoy playing on grass - it suits my game," Vesnina said. "I was a little bit unlucky last year, going through the qualifying and then losing first round to Kerber in a really close match, but I knew the results would come, I think I just needed to be a little more lucky and keep believing in myself."
Vesnina's win over the World No.6 is her fifth Top 10 win, the previous four coming against Svetlana Kuznetsova (2009 Dubai), Vera Zvonareva (2010 Sydney), Francesca Schiavone (2010 Cincinnati) and Samantha Stosur (2011 Charleston). This was Vesnina's first Top 10 win in more than two years.
"I'm really happy about that - I knew I hadn't beaten any Top 10 players this year yet," Vesnina said. "Before the match I was thinking that maybe this is the time. I'm really happy about this win today.
"It will bring me a lot of confidence for the rest of the season. It's always nice to win a match, but to beat a good player gives you twice as much energy and twice as much confidence for the next match."
Wickmayer followed a little later with a see-saw 62 16 75 win over the No.6-seeded Maria Kirilenko, almost letting the third slip away - she originally led 5-2, and even had three match points at 5-3 - but after watching things draw even again at 5-all, Wickmayer closed fast with two quick games.
"Maria and I played in Australia - I lost in two sets, but it was two tough sets," Wickmayer said. "I knew going into the match it was going to be hard and really tough, because she's playing really well and I think she is having one of her best years so far, breaking into the Top 10 for the first time too.
"I went out playing very aggressively and taking time away from her. The third set I knew was going to be a battle - I was 5-2 up, one break, serving for the match having two match points, and serving a double fault. But all the credit to her - she played really well from there, really aggressive and kept going for her shots. I was pulling back a little bit, maybe I was nervous to serve out the match.
"But in the end I'm really happy I could stay aggressive and positive and keep believing in myself."
Wickmayer's win over the World No.10 is her fifth Top 10 win, the first four coming against Agnieszka Radwanska (2010 Fed Cup), Li (2011 Dubai), Marion Bartoli (2012 Stanford) and Petra Kvitova (2013 Eastbourne - yesterday, making this the first time she has beaten two Top 10 players the same event).
Vesnina leads Wickmayer in their head-to-head series, 2-1, and won their only grass court meeting too.
"Elena has been playing great," Wickmayer said. "She just won the doubles at the French Open, came here and is in the semis. She beat some really good girls this week too. Every match is a fight here - I'm really excited to be in the semis, and I'm really looking forward to playing. We'll see how it goes."