Upsets abounded during a week of anarchy in two WTA tournaments and the Davis Cup quarterfinals.  Here’s an attempt to make sense of the mayhem that extended from Japan to Mexico.

Studs:

Roger Federer:  Not many teams can field a 17-time major champion as the singles No. 2.  Back in the top four after Miami, Federer extended his confident form this season with a pair of straight-sets victories over Kazakhstan.  The second of those wins came in the decisive fifth rubber and sent Switzerland into the semifinals.

Fabio Fognini:  Flaky at times against elite opponents, Fognini impressed on red clay in Naples against Andy Murray.  He curbed his fondness for creating drama by snuffing out the two-time major champion in straight sets, a win that Italy needed to survive.  Granted, Murray plays well below his best on clay, while Fognini specializes in the surface.  But two singles victories this weekend revealed the Italian as a worthy Davis Cup No. 1.

Czech Republic:  The two-time defending champions in Davis Cup usually lean on the tandem of Tomas Berdych and Radek Stepanek.  Without Berdych, their best player by far, the Czech Republic enlisted Lukas Rosol for an away tie in Japan.  And Rosol came through, as did the 35-year-old Stepanek, by sweeping a Japanese team lacking its own best player in Kei Nishikori.  Berdych probably will return for their semifinal, but the Czechs impressed by showing more depth than expected. 

Davis Cup fifth rubbers:  Three of the four quarterfinals ended in this climactic phase, although none of the three matches produced much drama.  While Federer eased past Andrey Golubev, Andreas Seppi made short work of James Ward in Naples.  Even Gael Monfils, usually cut from Fognini’s cloth, conceded just nine games in substituting for Julien Benneteau.  His victory over an unheralded German gave France its first comeback from a 0-2 deficit since 1996.

Andrea Petkovic:  Her first Premier title came without warning, for Petkovic had won more than one match at just two of her previous 13 tournaments.  She survived three three-setters en route to winning Charleston, including two comebacks from losing the first set.  Being a woman of extremes, she also won 31 of 33 games during one stretch in the first three rounds.  Petkovic overcame a disastrous start in her semifinal to outlast Canadian phenom Eugenie Bouchard, and she shouldered the role of the favorite with poise in dismissing an unseeded opponent a day later. 

Ana Ivanovic:  Between 2009 and 2013, Ivanovic did not win a title on an outdoor hard court.  Through barely three months of 2014, she now has two outdoor hard-court titles to her credit.  Ivanovic’s most notable victory in Monterrey came in a semifinal against former No. 1 Caroline Wozniacki.  That edgy match featured 11 service breaks in two sets but ran the Serb’s record to 6-2 against the top 20 this year.  Improving to 12-3 in finals at non-majors, Ivanovic tied Agnieszka Radwanska and compatriot Jelena Jankovic for sixth place in career titles among active players. 

First-time finalists:  Three seeds at the Family Circle Cup fell prey to Jana Cepelova, who had won just 18 matches and never reached a semifinal before this week.  A second-round ambush of world No. 1 Serena Williams seemed less like an accident with each upset that followed.  The 20-year-old will see her ranking rise sharply from its pre-Charleston position at No. 78.  If Cepelova builds on her breakthrough, Slovakian tennis will have more to watch than Dominika Cibulkova.

The other Serbian JJ, Jovana Jaksic, never has won a WTA match outside Monterrey.  In that small Mexican city, however, Jaksic is a different player.  She followed her first career victory in Monterrey last year with a finals run this year.  Jaksic also revealed a taste for drama similar to her fellow Serbs, saving three match points in the second round and battling through a three-hour semifinal. 

Belinda Bencic:  The junior No. 1 achieved another milestone with her first WTA semifinal.  Not long after turning 17, Bencic stunned two familiar names in Maria Kirilenko and third seed Sara Errani.  She fell to flavor-of-the-week Cepelova in a final-set tiebreak that revealed her inexperience, but fans are starting to know her as a face rather than just a name.

Eugenie Bouchard:  En route to the semifinals, Bouchard notched two impressive victories.  She avenged a three-set loss last fall to Venus Williams, off to a strong start this year.  And then Bouchard continued her dominance against Serbs by knocking off world No. 6 Jelena Jankovc for her second top-10 upset of the year. 

Kimiko Date-Krumm:  The 43-year-old from Japan reached her first semifinal outside Asia since launching her historic WTA comeback in 2008.  Like Ivanovic, Date-Krumm relished the fast court in Monterrey, where she spent over 11 hours in singles and doubles.  Like Cepelova, she built on her upset of the top seed (Flavia Pennetta) with victories over less renowned competition. 

Duds:

French and Swiss No. 1s:  Both Jo-Wilfried Tsonga and Stanislas Wawrinka won crucial fourth rubbers to keep their nation’s hopes alive, but losses on Friday extended their inconsistent form of recent week.  Tsonga fell to an opponent barely inside the top 100 after holding two match points in the fourth set.  (One of the match points saw him spray an open-court volley needlessly wide.)  Wawrinka dug Switzerland an early hole by falling to Andrey Golubev in the opening rubber.  The struggles of the two No. 1s turned two ties that should have been routine into nail-biters for the home fans.

Top two women’s seeds:  While Miami champion Serena Williams traveled to Charleston, Indian Wells champion Flavia Pennetta headed south to Monterrey.  As it turned out, both women headed south in a hurry.  A sluggish Williams dropped serve five times in her loss to Cepelova, her first in the opening round of any tournament since Roland Garros 2012.  Toppled by Date-Krumm in the first round of Monterrey, Pennetta probably hasn’t emerged from the glow of her stunning achievement in the desert.

Maria Kirilenko:  The glamorous Russian dropped her first match of a belated start to 2014.  Kirilenko, set to marry NHL star Alex Ovechkin soon, returned from a knee injury in Charleston.  She never quite recovered from a slow start in her loss to Bencic.  Brighter days surely await for a woman who cracked the top 10 less than a year ago.

American women:  Of the 11 who entered Charleston, none reached the quarterfinals.  Beyond Serena’s shock, fifth seed Sloane Stephens and 15th seed Madison Keys also underwhelmed as their inconsistent seasons continued.  Julia Boserup provided some consolation in Monterrey by reaching her first career quarterfinal, never having won a WTA main-draw match before.