The United States Greco-Roman wrestling team continued it strong showing at the Olympic wrestling competition at the Sydney Convention and Exhibition Centre in Darling Harbour, during action in the morning session on Tuesday, September 26.    Two U.S. wrestlers completed their preliminary competition with victories, and claimed their pools, advancing to the championship bracket: James Gruenwald, Colorado Springs, Colo. (Sunkist Kids) at 57 kg/127.75 lbs. and Rulon Gardner, Afton, Wyo. (Sunkist Kids) at 130 kg/286 lbs.    Gruenwald got the day off well, defeating veteran Igor Petrenko of Belarus. Petrenko was hit for a caution and one point penalty at the 47 second mark, then Gruenwald turned him with a gut wrench for two points and a 3-0 lead. With seconds left in the first period, Gruenwald scored a takedown for a 4-0 lead at break. The second period was evenly contested, with no scoring. Petrenko tried a lift in the last 10 seconds, which Gruenwald blocked.    Gruenwald advances to the quarterfinals, where he will face two-time Olympic bronze medalist Zetian Sheng of China. The lowest that Gruenwald could place is sixth in the weight division.    Gardner defeated Giuseppe Giunta of Italy, by a 2-1 overtime referee's decision. He scored a takedown and one-point turn in the first period, and led 2-0 at break. The second period got a little scrappy, as both athletes mixed it up pretty vigourously. No points were scored in the second period. In overtime, Gardner was hit with a caution and one for fleeing, and bout bout ended 2-1.    Gardner won his pool to advance to the semifinals, where he will face Juri Yevseychyc of Israel.  He is just one match away from going for the gold, and a possible battle with the unbeaten legend, three-time Olympic champion Alexander Karelin of Russia. The lowest that Gardner could place is fourth in the weight division.    Kevin Bracken (Chicago, Ill./New York AC) placed sixth at 63 kg/137.75 lbs., dropping his fifth-place match to Kurbanov of Uzbekistan by a 10-0 technical fall. Bracken gave up five points in the first period, then was exposed for two throws in the second period for the final 10-point margin at 4:06.    Heath Sims (Huntington Beach, Calif./Dave Schultz WC) completed his pool competition at 69 kg/152 lbs. with a victory, beating Nagata of Japan by a 4-2 score. Sims needed to score a pin or a technical fall to win his pool. By beating Nagata, all three athletes in the pool had 1-1 records, but Sims had the least classification points because he did not score in his loss.    It will be a big evening for the U.S. Greco-Roman program, as Matt Lindland (Milwaukie, Ore./Sunkist Kids) goes for the gold at 76 kg/167.5 lbs., and Garrett Lowney (Appleton, Wis./Minnesota Storm) battles for the bronze medal at 97 kg/213.75 lbs.    U.S. results    Tuesday, September 26, 9:30 a.m. session    58 kg/127.75 lbs. - James Gruenwald, Colorado Springs, Colo. (Sunkist Kids)    dec. Igor Petrenko (Belarus), 4-0    63 kg/137.75 lbs. - Kevin Bracken, Chicago, Ill. (New York AC)    Fifth Place match - lost by tech. Fall to Bakhodir Kurbanov (Uzbekistan), 10-0, 4:06    69 kg/152 lbs. - Heath Sims, Huntington Beach, Calif. (Dave Schultz WC)    dec. Kasuhiko Nagata (Japan), 4-2    76 kg/167.5 lbs. - Matt Lindland, Lincoln, Neb. (Sunkist Kids)    no matches this session - will be in gold-medal finals Tuesday night    97 kg/213.75 lbs. - Garrett Lowney, Appleton, Wis. (Minnesota Storm)    no matches this session  - will be in bronze-medal finals Tuesday night    130 kg/286 lbs. - Rulon Gardner, Afton, Wyo. (Sunkist Kids)    won by ref. dec. over Giuseppe Giunta (Italy), 2-1, ot, 9:00