Rafael Nadal during his match against Australia’s Alun Jones on Wednesday. (AFP)

On the eve of the US Open, Rafael Nadal was preparing to take the next flight home to Spain. His left knee was so painful after practising on Sunday, it was “impossible,” according to his uncle and coach, Toni Nadal, for him to play.

Two days of rest and treatment later, Nadal — the world’s No. 2-ranked player — found himself battling on Arthur Ashe Stadium Court against the unseeded and little known Alun Jones, a 27-year-old from Australia making his Open debut.

Jones once dug holes for his father’s dam construction project while temporarily retired from tennis three years ago, having earned more recognition in the sport for his bit part in the movie Wimbledon. Until Wednesday.

Jones had broken Nadal for a 4-3 lead in the third set, moving two games away from a two-sets-to-one lead.

But Nadal called for the trainer, had the tape on his left knee replaced, and quietly gritted out a first-round victory — 7-5, 3-6, 6-4, 6-1 — that cast a shadow on his remaining Open path.

“Maybe if I was in another tournament, I would not have gone to the court today,” Nadal said.

“But the US Open is a very big tournament for me. Two days ago I was much worse. Today I didn’t move much but I played, so that’s good news.”

Nadal — who has tendinitis and inflammation in his left knee — compounded the tendinitis in his right knee that he dealt with during his epic five-set loss to Roger Federer at Wimbledon.

But at least that was on a more forgiving grass surface. On the pounding hardcourts, a surface he is still trying to conquer when healthy, the injury adds yet another obstacle. “Sure, is difficult to play like this, especially here, no?” he said.

Nadal said he had a magnetic resonance imaging exam on Tuesday that did not show the injury to be a big problem. And even though he said he first felt the tendinitis four years ago, at age 17, he again insisted it was “not an important injury.”

DAY III RESULTS

Men’s singles, Round I — Philipp Kohlschreiber (Ger) bt Mariano Zabaleta (Arg) 6-2, 6-2, 6-4; Mikhail Youzhny (11, Rus) bt Nicolas Devilder (France) 6-0, 6-1, 6-2; Marat Safin (25, Rus) bt Frank Dancevic (Can) 7-5, 7-6(5), 7-6 (7); Ernests Gulbis (Lat) bt Potito Starace (30 Ita) 7-5, 7-6(4), 6-3, Michael Berrer (Ger) bt Michal Przysiezny (Pol) 6-1, 4-6, 6-1, 7-6 (4); Stanislas Wawrinka (Sui) bt Evgeny Korolev (Rus) 4-6, 6-3, 4-6, 6-4, 7-5; Robby Ginepri (US) bt Olivier Rochus, (Bel) 6-0, 6-3, 6-1; Jo-Wilfried Tsonga (Fra) bt Oscar Hernandez (Esp) 7-5, 6-1, 6-3; Tommy Robredo (8, Esp) bt Bobby Reynolds (US) 6-3, 7-6 (5), 6-1; Carlos Moya (17 Esp) bt Bjorn Phau (Ger) 6-1, 6-2, 6-4 Mardy Fish (US) bt Bruno Echagaray (Mex) 6-4, 6-1, 6-2 Rafael Nadal (2, Esp) bt Alun Jones (Aus) 7-5, 3-6, 6-4, 6-1; Igor Kunitsyn (Rus) bt Guillermo Garcia-Lopez (Esp) 4-6, 6-3, 7-5, 2-6, 7-5; Tim Henman (Gbr) bt Dmitry Tursunov (27, Rus), 6-4, 3-6, 6-3, 6-4; Janko Tipsarevic (Ser) bt Ryan Sweeting (US) 5-7, 6-2, 6-4, 6-2; Teimuraz Gabashvili (Rus) bt Fernando Gonzalez (7, Chi) 6-4, 6-1, 3-6, 5-7, 6-4 Round II — John Isner (US) bt Rik de Voest (Rsa), 6-3, 6-3, 7-6 (4); Roger Federer (1, Sui) bt Paul Capdeville (Chi) 6-1, 6-4, 6-4.

Women’s singles, Round II — Ana Ivanovic (5, Ser) bt Aravane Rezai (Fra) 6-3, 6-1; Sybille Bammer (19, Aut) bt Meghann Shaughnessy (US) 6-4, 6-3; Vera Dushevina (Rus) bt Ekaterina Bychkova (Rus) 6-4, 6-3; Ekaterina Makarova (Rus) bt Ai Sugiyama (28, Jpn) 6-4, 4-6, 6-2; Elena Dementieva (14, Rus) bt Petra Cetkovska (Cze) 6-3, 6-2; Venus Williams (12, US) bt Ioana Raluca Olaru (Rom) 6-4, 6-2; Justine Henin (1, Bel) bt Tsvetana Pironkova (Bul) 6-4, 6-0; Alona Bondarenko (21, Ukr) bt Eleni Daniilidou (Gre) 6-4, 6-7 (3), 6-3; Marion Bartoli (10, Fra) bt Sara Errani (Ita), 6-4, 6-1; Alize Cornet (Fra) bt Caroline Wozniacki (Den) 6-2, 6-1; Dinara Safina (15, Rus) bt Kateryna Bondarenko (Ukr) 6-2, 6-1; Lucie Safarova (20, Cze) bt Andrea Petkovic (Ger) 6-3, 6-3; Jelena Jankovic (3, Ser) bt Olga Govortsova (Bel) 6-2, 6-2; Ahsha Rolle (US) bt Karin Knapp (Ita) 3-6, 6-4, 6-3; Vera Zvonareva (27, Rus) bt Elena Likhovtseva (Rus) 6-4, 6-2; Serena Williams (8, US) bt Maria Elena Camerin (Ita) 7-5, 6-2