Up until two weeks ago, Gilles Muller of Luxembourg had won $74,851 in a year of circling the globe in Challenger events, and had a dismal 3-4 record on the ATP tour in 2008. Since then, he has won seven matches in a row at Flushing Meadows, three in the qualies and four in the main draw, to guarantee himself a payday of at least $140,000 and a chance at the final jackpot of $1.2 million.

Muller, ranked 130 in the world prior to the Open, on Tuesday upset world No. 5 Nikolay Davydenko in four sets, closing it out in a dramatic 12-10 tiebreaker. Bud Collins wrote of Muller in The Boston Globe on Sunday: “A loose-limbed, 6-foot-5-inch 25-year-old, Muller is a rambler like all tennis players. However, most of his time is spent in the minor tournaments, where the conditions and cash leave much to be desired. Remote locations in India, Turkey, Britain, Ireland, Finland, Germany, the US, Spain, were on his itinerary.

“I made $3,000 last week, quarterfinals in Istanbul,” Muller told Collins, “but most of the time your expenses are greater than your prize money.”

Muller next will run into Roger Federer in the quarters. It’s unlikely the last qualifier standing can keep it going, and he has to be exhausted going into his eighth match in less than three weeks. But I’m hoping he can do it.

Tennis needs a Rocky - even if he is from Luxembourg.