Write a question about the following article: The Steelers started their regular season, against the Houston Texans, in front of 64,001&#160;spectators at Heinz Field in Pittsburgh. The Steelers drove the ball 52&#160;yards on their opening drive, with their biggest gain coming on a 17-yard run from quarterback Ben Roethlisberger. Willie Parker scored a touchdown at 5:44 of the opening quarter and added a second touchdown in the following quarter. After a LaMarr Woodley interception the Steelers extended their lead to 21&#160;points when Roethlisberger completed a 13-yard touchdown pass to Ward. With 4:34 remaining in the half, former-Steelers' kicker Kris Brown converted a 34-yard field goal. Pittsburgh led the game 21-3 as time expired on the first half. In the second half, Parker scored his third touchdown of the game&#8212;surpassing his touchdown total for the entire 2007 season&#8212;and was named the AFC offensive player of the week for his performance. Pittsburgh's defense held Houston to six&#160;yards on their ensuing drive and the Steelers drove 80&#160;yards to take a 35-3 lead. The Texans scored two touchdowns in the final quarter, but Pittsburgh's James Harrison led the team with three sacks&#8212;forcing a fumble on the third&#8212;and the Steelers won their first game of the season starting out 1-0.
How many points did the Steelers win by?