Everyone knows what to expect when John Isner faces Ivo Karlovic:  aces, tiebreaks, short service games, and painfully few break points.  The two tallest men in the top 100 fell a bit short of expectations in the category of aces when they met in Acapulco on Tuesday, combining for only 23.  But Isner and Karlovic lived up to expectations in the other categories, delivering a two-tiebreak affair with just a single break of serve per player.  And it was Karlovic who won each tiebreak by a single mini-break to send home the top-ranked American in the first round.

The matches of each man resist analysis because they tend to hinge on a tiny handful of points, as was the case here.  Isner may have arrived in Acapulco weary from three three-setters and a late-night semifinal in Delray Beach last week.  But whether fatigue played a role in the one service point that he lost in each tiebreak, or in the single break  that he yielded, is impossible to discern.  What is much more discernible is the strong season that Karlovic has enjoyed.  Even before defeating Isner, the giant who turns 35 this week already had produced a victory over a top-10 player (Tomas Berdych), an ATP finals appearance (Memphis), and a record-setting 44-ace barrage at his home tournament (Zagreb).

Isner could not capitalize on his momentum from last week, but two European men could.  Mercurial competitors Ernests Gulbis and Alexandr Dolgopolov had won the Marseille title and reached the Rio de Janeiro final, respectively.  On Tuesday in Acapulco, each man routed a quality first-round opponent.  While Gulbis dropped just two games to Yen-Hsun Lu, Dolgopolov conceded just four to Canadian prodigy Vasek Pospisil.  Gulbis shifted smoothly from European indoor hard to North American outdoor hard courts, and Dolgopolov did not miss a beat in the more difficult transition from clay to hard.

Nor did Pablo Andujar, the man who held two match points against Rafael Nadal in a Rio semifinal.  Andujar came out firing against Andy Murray, much as he had against the world No. 1, and he raced to a one-set lead against a top-10 opponent for the second time in four days.  The clock struck midnight on this Cinderella more quickly in Acapulco than it had in Rio, however.  Although he dropped serve to start the second set, Murray regrouped to reel off six straight games and 12 of the last 14 overall.  Joining him in the second round was top seed David Ferrer, a comfortable winner earlier in the evening.

Like the top two seeds in the men’s draw, the top two seeds in the women’s draw solved their first tests.  Dominika Cibulkova secured her first victory since the Australian Open semifinal, where she had defeated Agnieszka Radwanska.  This time, the runner-up in Melbourne defeated Radwanska’s younger sister, Urszula Radwanska.  Australian Open semifinalist Eugenie Bouchard also started her Acapulco campaign convincingly by dominating Israeli veteran Shahar Peer.

Although Isner went home earlier than he had hoped, Acapulco still produced encouraging news for some of the Americans in the main draw.  Among them was Donald Young, who had lost eight consecutive sets since reaching the third round of the Australian Open.  Young retired in the final round of the qualifying draw against compatriot Tim Smyczek, yet he managed to enter the main draw as a lucky loser and defeat Jarkko Nieminen there.  (Ironically, Smyczek lost his first match to Gilles Simon.)

On the women’s side, the uneven 2014 season of Madison Keys continued with a first-round loss, although Keys had won three matches to qualify for the main draw.  Zhang Shuai became the first woman in 13 months to defeat the hard-serving American after losing the first set.  Brighter news came from another qualifier, Victoria Duval, who had defeated junior No. 1 Belinda Bencic to qualify for the main draw.  Once granted that opportunity, Duval took advantage by dispatching Iveta Melzer (formerly Benesova) in straight sets.