Carlos Alcaraz roared home for a 6-2, 4-6, 6-3, 6-1 victory over 186th-ranked Australian Li Tu on Tuesday to launch his bid to add the US Open to the Roland Garros and Wimbledon titles he claimed this year. The 21-year-old Spaniard pushed his Grand Slam winning streak to 15 matches as he tries to join Rod Laver and Rafael Nadal as the only men in the modern era to win the French Open, Wimbledon and the US Open in the same year. He got off to a hot start, seizing a 4-0 lead on the way to pocketing the first set. But Tu, who came through qualifying, got to grips with the imposing Arthur Ashe Stadium and Alcaraz’s serve to take the second set. He tried to keep the pressure on in the third, but Alcaraz’s break for a 4-3 lead opened the floodgates, the Spaniard winning the eight straight games to take the third set and build a 5-0 lead in the fourth. But Tu wouldn’t go quietly, saving a pair of match points before Alcaraz closed it out with a love service game. “I’m really happy to get through and get a chance to be better the next round,” Alcaraz said. “Obviously, I felt well on court. I think I hit the ball well. I moved well. “A few things that I have to improve if I want to, you know, keep going in the draw, but obviously I have to give credit to him as well that he played really good tennis and today surprised me a little bit in the second set.” Alcaraz had 50 winners and 30 unforced errors. Eighteen of those errors came in the second set, when he lost three straight games. That included dropping his serve to surrender the set, Tu finally converting his fifth set point.