BANGKOK (AFP) -- After a rain-drenched start, the PTT Bangkok Open got underway Tuesday with former world number 11 Meghann Shaughnessy of the U.S. moving into the second round, beating India's rising star Sania Mirza 6-4 6-4.

Shaughnessy will face Germany's Julia Schruff, who upset the world number 69 from Finland Emma Laine 6-4 7-6 (7-5) on the second day of the WTA tournament.

Twenty-seven-year-old Shaughnessy began well, but the game looked close toward the middle of the first set with Mirza tying the score at 3-3.

However, the American broke Mirza's serve to establish a 5-3 lead and used her serving game to close the first set at 6-4.

In the second set, Shaughnessy broke the Indian in the opening game and eventually claimed a 6-4 victory.

Shaughnessy, who reached world number 11 in 2001, said the rain initially hampered her play, but said her serve was the key to beating Mirza. "She is a great player," Shaughnessy said of her opponent. "She goes for her shots with her forehand being great. She has a great backhand and cut as well."

Schruff, the German world number 73, made a perfect start taking a 4-0 lead over Finland's Emma Laine before taking the opening set 6-4.

However Laine played well in the second set taking it to 6-6 draw and forcing a tie-break, which the German eventually won 7-5.

Also Tuesday, Thai number one Tamarine Tanasugarn beat Colombia's Catalina Castano 6-0, 7-6(7-5) in a match interrupted by rain.

Tamarine took the first set 6-0 in just twenty minutes, but the Colombian player picked up her game with the second set going to 6-6. The match was suspended as Tamarine held a 3-1 lead in the tie break.

Play resumed late Tuesday after a three-hour break, with Tamarine winning the tie-break 7-5.

Tamarine will meet either Jamea Jackson of the United States or Melinda Czink of Hungary in the second round of the tournament.