HOUSTON —Brett Myers pitched a complete game, Lance Berkman hit his first grand slam since 2008 and the Houston Astros beat the Cubs 6-1 on Tuesday night.It is the 10th career complete game for Myers (8-6) and his first since May. He allowed four hits and struck out a career high-tying 12 batters.Berkman’s fifth career grand slam came in Houston’s six-run seventh inning with the team leading 2-0. The shot, his first since Aug. 12, 2008, sailed over the bullpen and landed in the stands behind it in right-center field.Myers extended his club record for consecutive starts of at least six innings to begin a season to 21 with his performance.Ted Lilly left after 5 with the game scorless.Losing pitcher Andrew Cashner gave up all Houston runs,including the slam to Berkman.Tyler Colvin homered off Myers in the 9th for the only Cub run.