Victoria Azarenka is braced for a barrage of big serves from Serena Williams as she attempts to make her first Wimbledon final.
Williams has hit 61 aces, 27 more than any other female player, in her hunt for a fifth Wimbledon singles title.
"She has a huge serve, every player that played against her felt that," said Australian Open champion Azarenka.
The pair meet in the second of Thursday's two women's semi-finals on Centre Court.
Third seed Agnieszka Radwanska of Poland will play Germany's eighth seed Angelique Kerber in the other semi-final.
Second seed Azarenka has not dropped a set en route to the last four and, following Maria Sharapova's fourth-round exit, is the highest-ranked player remaining in the draw.
However, the 22-year-old has won just once in eight previous meetings with sixth-seed Williams, whose ranking has not fully recovered from a year out with a pulmonary embolism.
"I don't really like to look back in history because every time you step on the court it's a new story," said Azarenka.
"You kind of write your own history every time. We had good matches. We had bad matches. We'll see.
"I think everybody takes a Grand Slam with a little bit more attention and wants to win more."
Williams, a 13-time Grand Slam champion, knocked out last year's winner Petra Kvitova in the previous round and believes the latter stages draw the best performances from her.
"You can't play a defending Wimbledon champion or Grand Slam champion and not elevate your game," said the 30-year-old.
"I had to weed out the riffraff and just get serious."
On Azarenka, she added: "She's playing unbelievable. I think she's played so well this year. Already having a Grand Slam under her belt is really great. She did it in such style, so it's not going to be easy if I play her.
"You know, it's going to be another match where I have absolutely nothing to lose. I can just go out there and enjoy myself and have fun."
Radwanska and Kerber, who will kick-off women's semi-final day at 13:00 BST, will provide a Grand Slam final debutant regardless of the result.
Radwanska, who won the girls title at the All England Club in 2005, suffered a shock defeat to the unseeded Kerber in the second round of the 2011 US Open.
Since that run to the semi-finals at Flushing Meadows, Kerber has risen 84 ranking places to 8th in the world and had five match points in the final of Eastbourne last month before losing to Tamira Paszek.
"I didn't really play my best tennis when I lost to her at the US Open, but then she won a couple more good matches afterwards," said Radwanska, 23.
"She's very consistent. She's really hitting the ball very well and moving well. She is just very solid. You really have to be patient and not try to finish the point in one ball.
"It doesn't matter who you play, to be honest. This is the semi-final, so it means that we have both already played a couple of good matches against seeded players."
The 24-year-old Kerber lost to British number four Laura Robson in the first round at Wimbledon last year and admits that her rise up the rankings since then has loaded expectations on her.
Should she overcome Radwanska she would be the first German woman into the final since Steffi Graf in 1999.
"It's a little bit different from last year at the US Open or last year at Wimbledon, because now everybody expects me to be in the second week and win matches," she said.
"I feel the pressure for sure."