Former world No. 1 Thomas Muster, currently ranked No. 1005 on the ATP computer, is still looking for his first win of the year after Benjamin Balleret ousted the greybeard Austrian 4-6, 7-5, 6-2 yesterday in the first round of the San Marino CEPU Open, a Challenger tournament in the tiny Republic of San Marino. Muster, now 43-years-old, un-retired last June after originally disappearing from the tour in 1999. The uber-competitive and feisty Austrian won 44 tournaments during his career — 40 of them on clay, including the 1995 French Open. Only Guillermo Vilas, with 45, holds more clay-court titles. Muster was clearly the clay-court stud of his day, but now he plays career journeyman still hoping to make it onto the tour by competing on the Challenger circuit — the minor leagues of professional tennis. What in the world is Muster doing? Maybe trying to become the oldest player to win an ATP Tour match. Jimmy Connors holds that distinction, reaching the quarterfinals at Halle in 1995 at age 42. Ballaret, a 28-year-old from Monaco, is ranked No. 432 and reached a career high of No. 204 in June of 2006. Muster can still grind it out on the slow red clay and for a while gave the Monte Carlo native a scare. The tenacious Austrian, with a set in hand, was up a break twice in the second set but couldn’t consolidate his advantage. Ballaret broke in the 12th game to even things at a set apiece. Fresher legs prevailed in the third set as Muster couldn’t keep up with his younger opponent. Since his return last July, Muster is 1-16 on the Challenger circuit and 0-2 on the ATP Tour. Ouch! Last week. Muster got a wild card at Kitzbuhel, where Philipp Kohlschreiber waxed him 6-3, 6-0. After the drubbing, Muster said: “I don’t plan on playing forever, but I’m still very much enjoying it.” You have to wonder, though, how much longer the “old dog” can tolerate the losing.