Luxembourg’s Gilles Muller and big-serving Sam Groth engaged in a throwback serve-and-volley duel straight out of the past Wednesday morning. Muller won the first-round matchup at the Taipei Challenger 7-6 (1), 7-6 (8), as both players charged the net relentlessly and never lost serve in the 1-hour, 46-minute tussle. The two have been among the hottest players on the Challenger circuit so far this year. Since March, the 30-year-old Muller, ranked No. 42 back in 2011, has won two of his last three Challenger events, and was a finalist in another earlier in the year. Groth, seeded fourth, won his maiden Challenger title (Rimouski) last month and was a finalist at Leon three weeks ago, while ascending to a career-high No. 136 ranking. The canonball-serving Australian also reached the quarterfinals at Brisbane, an ATP Tour event, in January. Muller, sidelined until January with a shoulder injury following a first-round loss at the French Open last year, ended 2013 at No. 368 in the world. With his win last week at Shenzhen, the 6-foot-4 lefthander has climbed back to No. 160, but was unseeded at Taipei. That was Groth’s misfortune. Based on form, both should have been meeting in the quarterfinals or later. With Groth blasting rockets on his first serve and Muller confounding the big Aussie with his swooping left-handed delivery, there was just one break point in the first set. That was in the seventh game, and Groth saved it. After winning his serve to go up 1-0 in the tiebreaker, Groth went walkabout. Muller got three mini-breaks to take the tie-break handily, 7-1. Clearly frustrated, Groth nevertheless mustered up and didn’t let it get to him. He pressured Muller in the opening game of the second set, earning two break points, but couldn’t cash either of them. He earned another break point in the fifth game, but Muller defended that one too. Groth held two set points in the second set tiebreaker, but double-faulted at 8-9 to cede victory to the Luxembourger. Muller had 10 aces and won 86 percent of the points on his first serve. Groth served 15 aces and won 85 percent of his first service points. Muller saved all three of his break points, while Groth defended his only one.