Senior editor Richard Pagliaro assesses the final fours at the Auckland, Brisbane, and Shenzhen WTA season-opening tournaments:

Auckland Semifinals

*(1) Agnieszka Radwanska vs. Jamie Hampton

(3) Yanina Wickmayer vs. (8) Mona Barthel*  
On the strength of seven service breaks, Hampton upset defending champion and former Wimbledon semifinalist Zheng Jie in the opening round. The American has broken serve 20 times in three matches, but that trend will be tough to sustain against Radwanska, the defending Wimbledon finalist. Once typecast as a counter-puncher, Radwanska’s skill at taking the ball early—particularly off the backhand—controlling the center of the court, and deploying the feel of a safe-cracker around net gives her the offensive edge. Hampton’s best shot is to play high balls to the Pole’s forehand and try to back her off the baseline, but that's not her style. Radwanska is a much more agile mover and should pick Hampton apart.  
Barthel and Wickmayer are both tall, power players at their best playing first-strike tennis. Wickmayer hasn’t yet lived up to the expectations established when she reached the 2009 U.S. Open semifinals, but the former world No. 12 is only a year older than Barthel and has won two of their three meetings. A fast start is critical as Barthel was 5-9 in three-setters last year; Wickmayer was 5-10, though one of those wins was a 6-4, 6-7, 6-3 decision over Barthel a little more than a month after the German’s crushing 6-1, 6-2 win in the Hobart final.

Barthel plays flat and fast, and can be streaky as a result. A shotmaker, she can smack a series of winners or misfire on over-ambitious drives down the line. Accuracy can be an issue, but I don’t believe Barthel will succumb to fear factor in this match, particularly if tie-breakers come into play. But Radwanska is the most complete player left in the field, and her ability to change the pace and spin of her shots, as well as her befuddling defensive skills, make her the overall favorite.

The Pick: Agnieszka Radwanska

Brisbane Semifinals

*(1) Victoria Azarenka vs. (3) Serena Williams

Anastasia Pavlyuchenkova vs. (LL) Lesia Tsurenko*  
The world No. 1 vs. the world’s most dangerous player is a rematch of the 2012 U.S. Open final. Azarenka’s track record against Williams is as soothing as sunburn—she’s 1-11 lifetime, including five losses in 2012—but can draw confidence from the fact she served for the title in Queens and has dropped only seven games so far in Brisbane.

Azarenka is arguably tennis’ top returner, but I regard Serena’s serve as the best in history, and she will attack Vika’s second delivery with a vengeance. Serena’s superior speed around the court, explosiveness on the run, and her ability to hit all areas of the service box with three different spins—flat, kick and slice—make her the pick.

Pavlyuchenkova was 1-5 vs. Top 10 opponents in 2012, but has attacked the ball with all the enthusiasm of a kid pounding a piñata in scoring wins over Petra Kvitova and Angelique Kerber this week. Maintaining focus and keeping her blasts between the lines has been a challenge for the former No. 13, but Pavlyuchenkova has too much power and experience for 116th-ranked lucky loser Tsurenko, who is playing her first WTA semifinal.  
Interestingly, Serena did not win a tune-up tournament before any of her five Australian Open titles, but looks highly motivated to do so here, which put her closer to succeeding Chris Evert as the oldest women’s No. 1. Williams craves pace and will get plenty of it from Pavlyuchenkova, whose grip-it-and-rip-it game is built around her massive forehand and improved serve. Look for Serena, who can hit with more spin, to work the width of the court, using some shorter, sharper angles to drag the Russian wide and coax her into low-percentage shots.  

The Pick: Serena Williams

Shenzen Semifinals

*(1) Li Na vs. (6) Shuai Peng

(5) Klara Zakopalova vs. Monica Niculescu*  
The Chinese rivals have split three-setters in their last two meetings. Neither woman gives up much ground behind the baseline, which makes controlling the first strike key. Though Li is a former French Open champion, she’s most at home on hard courts taking charge in baseline rallies. Playing with two hands off both sides, Peng is a pure ball striker, but Li is the better athlete and a bit more versatile. Peng tends to be the calmer competitor—she saved a match point in her quarterfinal win over Annika Beck—and Li’s serve, nerve, and forehand can sabotage her under pressure (she overcame 10 double faults in the quarterfinals). But Li is more dangerous from more areas of the court and has won four of five matches against her compatriot.  
Often overshadowed by bigger opponents, the 5’5” Zakopalova has relied on her fast hands and sound court sense to rack up more than 400 career singles wins. She tends to play cleaner tennis than Niculescu, who is prone to trying lower-percentage shots when pushed on the defensive. This is a match that will be decided at the baseline, and Zakopalova’s consistency, experience and fitness make her the pick.  
Working with coach Carlos Rodriguez, Li has tried to limit her emotional implosions and play with more positive emotions. The challenge for the former Australian Open finalist is producing under pressure at home, where her best tennis has eluded her. She’s looked tight at times, but if she keeps her head together and weathers the ebbs and flows of her serve, I look for Li to take the title.  

The Pick: Li Na