American John Isner reached his first ATP World Tour Masters 1000 semifinal as he battled past fourth-seeded Spaniard David Ferrer 6-3, 3-6, 6-3 here on Friday. After the first two sets were split, the No. 25-ranked Isner made the decisive move in the third set, winning 12 of the last 14 points. He broke Ferrer to 15 in the eighth game before serving out victory to love in one hour and 46 minutes. \"I feel great,\" declared Isner. \"It was my first Masters quarter-final, as well. I\'m just thrilled to have won tonight, given that Ferrer is such a tough player. He\'s No. 5 in the world for a reason. I played very well, and I\'m very, very happy.\" The 26-year-old Isner goes on to face French hope Jo-Wilfried Tsonga for a place in his fourth ATP World Tour final of the year. The American had a strong summer, winning the titles at the Campbell\'s Hall of Fame Tennis Championships in Newport and the Winston-Salem Open, and finishing runner-up at the Atlanta Tennis Championships. The 29-year-old Ferrer fell at the quarterfinal stage in Paris for the third time. The Spaniard, a winner of two ATP World Tour titles this season, dropped to a 56-17 match record. He will now travel to London to compete in the elite eight-man field at the ATP World Tour Finals, beginning on November 20.