As the men’s third round concludes, Tuesday features the entire fourth round of the women’s draw in a dramatic thrust forward to the marquee meetings late in the tournament.  Today, we cover all eight of those matches by taking the draw from top to bottom.

Azarenka vs. U. Radwanska:  Dominating her elder and more famous sister on this court a year ago,  the defending champion hopes to bounce back from an unimpressive three-setter on Monday night.  Azarenka struggled on serve for much of her first two matches, and she cited a cold as part of the explanation.  For her part, the unseeded Urszula has produced form far from cold with an upset over local darling Sloane Stephens before another solid effort over Jamie Hampton, the last American left in the women’s draw.  Although she covers the court effectively, this Radwanska has a much more standard playing style than her versatile sister, so Azarenka should feel comfortable if she can overcome whatever physical issues of her own linger.

Petrova vs. Wozniacki:  Only two ranking slots ahead of her opponent, Wozniacki has controlled most of their rivalry until a rout by the Russian last fall in Sofia.  The 2011 Indian Wells champion improved her level from the second round to the third, not only producing more consistent tennis but swinging more confidently on her groundstrokes.  But Petrova still has looked the more impressive of the two in the tournament’s early stage, overwhelming seeded foe Julia Goerges for the loss of just three games.  Her first serve should prove the key to this match, since she can frustrate Wozniacki by establishing control of the rallies from the outset.  By contrast, a low first-serve percentage can disrupt the rest of Petrova’s game and allow the counterpuncher to outlast her.  While both women can lose the rhythm on their forehands for extended stretches, each can rely on her crisp two-handed backhand under pressure.

Kerber vs. Muguruza:  Flying under the radar despite holding the fourth seed, the world #6 cruised through her first two matches in straight sets.  She now faces a qualifier who has needed to win five matches just to reach this stage.  A heavy hitter from both wings with a passing resemblance to Sorana Cirstea, Muguruza ousted Jovanovski and Makarova in three sets and followed those upsets with a more authoritative victory.  Her accumulated court time could hinder her in the physical rallies that Kerber prefers, but her success against Makarova will have prepared her for the weapons distinctive to a lefty’s game.  She aims to become the first qualifier to reach the quarterfinals here since Dulko in 2004.

Barthel vs. Stosur:  In a display of effortless baseline power, Barthel battered former champion Ivanovic out of the desert by striking clean winners from serve, return, and both groundstrokes.  Especially impressive was her backhand, which could play a crucial role in delivering a second straight upset.  Stosur deserves credit for reaching this round for just the second time in nine Indian Wells appearances, but her imbalanced game can cost her against someone of Barthel’s more complete weapons.  The most formidable shots on the court belong to the Aussie in her serve and forehand, so she will hope to avoid the backhand-to-backhand battles that would favor the German.  Nearly upsetting Azarenka in an early round last year, Barthel has looked the sharper, more confident player of the two this week as a February title may have galvanized her momentum.

Kvitova vs. Zakopalova:  The only singles match relegated to the modest Court 7, it represents an intriguing test of nerve for Kvitova.   She always struggles facing her compatriots, probably because of her friendships with many of them as Fed Cup teammates.  While Zakopalova won both of their previous meetings, they have not met in over five years and never at the WTA level.  In theory, Kvitova should hit through her countrywoman’s defenses with ease, for in no area other than defense is she the lesser of the two.  Her focus still grows too fitful too often as she matures, however, which will open the door for a steady Zakopalova to chip away patiently in the manner that has maddened similarly elite opponents.  If Kvitova seeks to rise from the lower part of the top eight, these are the matches that she needs to win.  Ever since her 2011 Wimbledon title, these are the matches that tend to slip away from her.

Kirilenko vs. Radwanska:  Brace yourselves for an epic in a rematch of a Wimbledon quarterfinal last year that spanned an entire day and two courts before ending 7-5 in the third.  Following the same scoreline was their meeting here two years ago, also claimed by Radwanska in the midst of her current five-match winning streak against the Russian.  Kirilenko has improved her power over the last eighteen months or so as she has risen to the threshold of the top 10, and an Indian Wells quarterfinal in 2012 illustrated how well her stylish game suits these courts.  Comfortable anywhere on the court, both women will venture to and from the net more often than many of their peers, trying to gradually construct points by outmaneuvering the opponent.  Both have looked vulnerable in earlier rounds by rallying from one-set deficits and struggling to close out matches.

Errani vs Bartoli:  Ranked consecutively at #8 and #9, they offer the first matchup of the tournament between two top-10 seeds.  Even more emotionally engaged than usual, Bartoli wildly fistpumped her way through a victory over Kuznetsova that featured equally wild oscillations in form but avenged a February loss.  Hardly more tranquil was Errani’s opening victory over fellow clay specialist Dominguez Lino, a match that featured 20 service breaks in its 26 games.  Unlike Ferrer, the Italian has adjusted successfully to the hard courts after a strong performance in Acapulco immediately before, and she can gain confidence from winning her two meetings with Bartoli last year (both on hard courts).  That recent success comes as a surprise, for the double-fister’s sparkling returns should pounce on her rival’s notoriously weak serves.  Asserting herself in return games against Kuznetsova with increasing determination as the match wore on, Bartoli should reap rewards if she sticks to a similar strategy and executes it as effectively.

Sharapova vs. Arruabarrena-Vecino:  A pedestrian performance by her standards, Sharapova’s third-round display more than sufficed to carry her past a top-25 opponents in straight sets.  Even without raising her quality significantly, then, she should not experience any sustained adversity in a match against a clay specialist barely inside the top 100.  Granted, Arruabarrena-Vecino already has notched two upsets of seeded opponents in Lepchenko and Vinci.  But the former has lost eight of her last ten hard-court matches, and the latter presented a type of challenge much less intimidating to the Spaniard than a level of power that she may never have seen before.  Suarez Navarro drew some errors by keeping balls low to the Sharapova backhand, less reliable than usual on Sunday.  That tactic, combined with prayers for another erratic day from the Russian, seems Arruabarrena-Vecino’s only chance to assert herself in this contest.