American John Isner served 21 aces as he edged past Thai wild card Kittipong Wachiramanowong 6-3 3-6 7-6.
Isner, seeded eighth, won a hard-fought encounter 6-3 3-6 7-6 in two hours and 12 minutes to move into the second round of the PTT Thailand Open in Bangkok.
Brazilian Thomaz Bellucci also advanced to the second round after saving 11 of 12 break points to defeat Guillermo Garcia-Lopez of Spain 6-4 7-6.
