MELBOURNE, Australia -- At 6-foot-10, you can sympathize with John Isner when he says he has a leg-room problem on airplanes.

Which is unfortunate, because after a 7-6 (4), 7-6 (6), 6-4 loss to Gilles Muller in the third round of the Australian Open, Isner will be making the long, cramped journey back to the U.S. far sooner than he had hoped.

Isner boasts arguably the most lethal shot in tennis, a wicked first serve, which against Muller reached 139 mph at times. But for Isner, who also hit a remarkable 30 aces, he forged just one break opportunity in the match -- one that he failed to convert.

Combined with Steve Johnson’s four-set loss to No. 5 Kei Nishikori, the U.S. men find themselves in familiar, hollow territory; they won’t have a representative in the fourth round of the Aussie for the fourth straight season -- an unfortunate circumstance for a country that is simultaneously producing a host of talented young women.

Isner came to Australia with new coach Justin Gimelstob, a move largely made to help the No. 19 seed quiet the Grand Slam fire alarm that’s been going off for years and to work on his overarching vice, the return of serve. But as we saw against Muller, Isner’s length can be an impediment. With arms as long as his, it’s a tough ask to first turn your shoulders and then swivel quickly enough to create any kind of offense on returns.

To Isner’s defense, Muller served with chilling efficiency, unleashing 24 aces of his own and winning 90 percent of points on his first deliveries. Muller, it should be pointed out, is somewhat of a feel-good story. The 31-year-old from Luxembourg was out of tennis for nearly a year after undergoing elbow surgery following the 2013 French Open. But he’s on to his first Grand Slam round of 16 in 3½ years.

For the record, Isner has now gone 12 Grand Slams without reaching a quarterfinal and has never, ever made a semi.

As for Johnson, he started off quickly against Nishikori, the 2014 US Open runner-up. Johnson won a lengthy first-set tiebreaker before Nishikori figured out he was in fact Nishikori. Johnson, the two-time NCAA champ from USC, fell 6-7 (7), 6-1, 6-2, 6-3.

At this point, there won’t be any new questions, new concerns or new explanations on the state of U.S. men’s tennis. We’re more or less repurposing the same narrative that has dented the image of the Americans since Andy Roddick reached the Wimbledon final in 2009.

But even though it’s not a new story, it’s still a troubling one.