From veterans to teenagers, power to finesse, funny to feisty, there's a pleasing variety of playing styles and personalities with a lot to offer.
One is a surprise, the other is not, and the contrasts don't stop there. Bouchard, the surprise who emerged from the quarter vacated by Serena Williams, is the 2012 Wimbledon junior champ and a teenager who plays older than her years. Li is over 30 and the 2011 French Open champ yet is trying to improve like a player just starting out.
Bouchard is a counterpuncher, a good mover who absorbs pace and redirects the ball to keep opponents off balance and create openings.
"I think I just really try to take the ball early," she said. "I think that's good because it takes away time from the opponent. She has less time to guess where I'm going or try to read where I'm going. I think that's an advantage I try to use on the court."
As she showed in coming from a set down to defeat Ana Ivanovic in the quarterfinals, the 19-year-old Canadian is a natural on the big stage. She began to really harness her game after the US Open last year, significantly improving her performance and results. But she lacks a big weapon and can be vulnerable against big hitters.
Li, on the other hand, is a puncher -- a power player who is trying to develop her serve-and-volley with coach Carlos Rodriguez, who worked with retired former No. 1 Justine Henin. Though she can hit almost anyone off the court when playing well, nerves can get the best of her.
Their personalities are equally different. The glamorous Bouchard, who admires Maria Sharapova, not only wears the Russian's clothing line but shares her inclination not to get close to other players.
One exception is the fun-loving Laura Robson, a good friend from juniors -- two years ago, the two produced an entertaining music video featuring various players showing off the latest dance moves. The Australian crowds, including the boisterous, chanting "Genie's Army," have been impressed -- or at least they were until Bouchard was asked in her last on-court interview who she would like to date.
There were boos as she replied, "Justin Bieber."
Li's on-court interviews are typically big hits, starting from her run to the final in 2011 and all the comedic performances about her husband that accompanied it. After reaching two finals at this event, the popular Li can expect the crowd to lean her way in Thursday's match. The contest will also likely be decided by her winners and errors.
Bouchard is not expected to beat herself, so Li will need to manage the pressure of being the favorite and take effective control of the points. Bouchard, who will be playing her first Grand Slam semifinal, is aware of the gap in experience with Li but isn't conceding any advantage.