Top seed Andy Roddick was embroiled in a tight second round match at the RCA Tennis Championships against Swiss qualifier Michel Kratochvil before bad weather intervened in Indianapolis on Wednesday.
Roddick, the defending champion, was leading 6-4, 2-5 when heavy rain suspended play at the hardcourt event which serves as a warm-up for the U.S. Open.
The match will be completed on Thursday afternoon and the winner will go on to face 15th-seeded American Robby Ginepri, a 6-3, 3-6, 6-2 winner over Frenchman Sebastien de Chaunac, later in the evening.
There were several upsets in earlier matches, including unseeded Gregory Carraz's 7-6, 7-6 win over fifth-seeded American Mardy Fish.
Two other seeded players also withdrew from the event, both citing stomach problems.
Number seven seed Sjeng Schalken lost his first set to Jan Hernych 7-5 and trailed 1-0 in the second set before retiring.
Taylor Dent, the number nine seed, left before playing his match against Todd Reid after getting a bye into the second round.
Reid took advantage of the break by defeating Dent's replacement in the draw, Alex Kuznetsov 6-1, 7-5.
Third-seeded Sebastien Grosjean lost his opening set to compatriot Julien Jeanpierre in a tiebreak before rallying to take the remaining two sets by identical 6-2 margins.
Eleventh-seed Joachim Johansson also needed three sets to see off Britain's Greg Rusedski 6-7, 6-3, 6-4.
There were also victories for sixth-seeded Dominik Hrbaty, 12th-seed Nicolas Kiefer and 14th ranked Xavier Malisse.
