The men’s quarterfinals begin as the women’s quarterfinals conclude on Wednesday in Miami.  Two of the ATP Big Four collide in a blockbuster battle, but that’s not the only intriguing match to watch.

Andy Murray vs. Novak Djokovic:  This Big Four rivalry usually unfolds on stages grander than a quarterfinal at a non-major.  Djokovic and Murray have contested finals at every major except Roland Garros and two previous finals in Miami.  Showing the even balance in this matchup, they have split their four major finals and their two Miami finals.  Djokovic probably holds a greater edge than usual over Murray, who has won the first set in each of their last six meetings but finished off just three of them.  Although he survived more than dominated at Indian Wells, the Serb will bring plenty of confidence from claiming the first Masters 1000 title of 2014.  Murray has not defeated a top-10 opponent or reached a final since winning Wimbledon last summer, although the Miami defending champion handled world No. 11 Jo-Wilfried Tsonga with ease on Tuesday.

Roger Federer vs. Kei Nishikori:  A three-hour marathon against David Ferrer on Tuesday may have drained Nishikori’s energies for Federer a day later.  He defeated the Swiss star last spring on the red clay of Madrid, the least favorable surface for both men.  But Federer has produced far more convincing tennis this season than he did in 2013, regaining his health and his poise.  A 49-minute rout of Richard Gasquet in the fourth round marked his fifth victory over a top-10 opponent in 2014, more than he earned in all of 2013.  Federer nearly won Indian Wells by playing fast-court tennis on a slow hard court, so there is no reason to doubt that he could shine in Miami with the same tactics.  Nishikori needs to take the initiative in rallies rather than playing defense from far behind the baseline.  That’s much easier said than done considering how well Federer has served recently.

Dominika Cibulkova vs. Agnieszka Radwanska:  American fans might remember the Stanford final that this matchup produced, a three-set rollercoaster pitting Cibulkova’s fiery offense against Radwanska’s crafty counterpunching.  Prevailing on that day, Cibulkova also vaulted the Pole in an Australian Open semifinal this January.  Revenge for that rout may not come easily for Radwanska.  The 2012 Miami champion fell prey to a leg injury during the Indian Wells final and has impressed only intermittently in Miami.  Although the slow hard courts suit her playing style, they also give Cibulkova time to run around her backhand to hit forehands.  The Slovak returned brilliantly in her victory over Venus Williams a round ago, and she will look to punish Radwanska’s vulnerable serve.  Her own serve is equally vulnerable, though, so a quarterfinal filled with breaks could unfold. 

Caroline Wozniacki vs. Li Na:  Steady meets streaky in the latest edition of an engaging WTA sub-rivalry.  Most of their matches have been decided on Li’s terms, for she wields the superior firepower and the more aggressive mind.  Their signature clash came at the 2011 Australian Open, when Li saved match point in the second set before battling past Wozniacki to her first major final.  Now a two-time major champion, she faces a Dane whose ranking has dipped to its lowest ebb (at No. 18) since she soared to the top spot.  That lesser status has not stopped Wozniacki from rolling past her last two opponents for the loss of just two games.  She also defeated Serena Williams on this court two years ago, one of her best victories ever.  To reach her first Miami semifinal, Li will need to stay more patient than she has in uneven efforts since winning the Australian Open.