ATP columnist Nick Nemeroff takes his best shot at calling three of the most intriguing men’s matches on Day 4.

Marin Cilic vs. Gilles Simon

Gilles Simon’s status going into his first-round match against Daniel Brands was questionable at best. Some reported that the Frenchman had withdrawn from the tournament, while others reported that an ankle injury had immobilized Simon and reduced him to crutches. Regardless, Simon stepped out on court, came back from two sets to one down, saved seven match points, and won 16-14 in the fifth set in a match that lasted four and a half hours.

Cilic’s first-round match, while far less dramatic, wasn’t a cakewalk either. After dropping the first two sets against Marcel Granollers of Spain, Cilic stormed back to win the final three sets comfortably.

Simon entered the Australian Open with only a single match under his belt, a straight-sets loss to Marius Copil in Brisbane. Cilic warmed up in Sydney and Brisbane, where he failed to advance past the quarterfinals in both tournaments, but was able to grab victories over Denis Istomin and Grigor Dimitrov.  He trails the head-to-head in this series 3-0, but the two men haven’t played since 2008.

It’s hard to imagine Simon having much left in the tank after his epic clash with Brands. While Cilic did go the distance with Granollers, it wasn’t an excessively taxing match for the Croat.

Look for Cilic to exploit Simon’s battered physical state and make the Frenchman earn every point, thereby giving Simon a steady dose of his own medicine—a cruel reversal of tactics. Given the amount of vomiting, hallucinating, and fainting occurring on the Australian Open grounds, it will be interesting to see if the tenacious Simon can withstand the conditions during a match that will likely be played during the middle of the day.

Prediction: Cilic in four sets

Yen-Hsun Lu vs. Grigor Dimitrov

The clock is ticking for Dimitrov. Labeled by many as a potential future No. 1, the exceptionally talented Bulgarian has reached the third round of a grand slam only once in his career. He’ll be looking to overcome these grand slam demons when he takes on a veteran from Taiwan.

Lu’s biggest success at a grand slam came at Wimbledon in 2010, when he reached the quarterfinals after defeating Andy Roddick in a classic five-set battle. Lu has reached the third round Down Under on two previous occasions. Taiwan’s top player is coming off his first ATP final last week in Auckland, where he lost in two tiebreaks to John Isner.

In his first-round match, Lu dismantled qualifier and fellow countryman Jimmy Wang in three sets, while Dimitrov fought past American Bradley Klahn in four sets. Lu and Dimitrov have never played, and a match under the sweltering heat is probably not the setting where they would like to be introduced to each other.

Both men possess technically sound games and can deliver strong strikes off both wings. Dimitrov is certainly the more dangerous and talented player, but Lu’s level of experience should provide him with an advantage in terms of dealing with the perilous weather.

Dimitrov won’t be doing himself any favors if he attempts to outdo Gilles Simon and Daniel Brands by playing three hours and beyond. Considering how crisp Lu has looked in the last week and a half, don’t be surprised if Taiwan’s top man finds a spot in the third round.

Prediction: Lu in five sets

Gael Monfils vs. Jack Sock

Jack Sock is one of three American men remaining in the Australian Open. If Gael Monfils shows up and produces the brilliant tennis that he is fully capable of producing, the United States should be down to two players on the men’s side. But this is a big if.

Sock took out German Tobias Kamke in the first round and defeated the top German man, Tommy Haas, in Auckland last week before losing to Roberto Bautista Agut in the second round Monfils raced past another American, Ryan Harrison, in his opening match here, only needing one break in each set. Like Lu and Dimitrov, Sock and Monfils have never played.

Sock’s game is centered on how well his serve and forehand are clicking. When working in harmony, Sock can be an offensive nightmare for opponents. Against Monfils, Sock’s aggression level cannot afford to waver, since Monfils possesses uncanny speed and can defend as well as anyone on the planet.

While Sock is limited to attacking as he doesn’t possess any significant defensive capabilities, Monfils is equally adroit on offense and defense. The Frenchman should also be able to take immense advantage of the Jack Sock backhand. That stroke is by far his weaker wing, as it is for many American players, so Sock will be looking to escape any backhand-to-backhand exchange as quickly as possible. But consistently having to run around backhands all day against a player who will take advantage of the open court doesn’t bode well for the American.

The only reason Monfils should lose this match is because he doesn’t bring his best effort, which has happened on many an occasion during his career. His first match was a night match, and the scorching weather, which Canadian Frank Dancevic called “inhumane,” may do its damage to the Frenchman’s heart and will.

Prediction: Monfils in four sets