"I always expect myself to go out there and compete, succeed and work hard for my teammates," said Sampson, a native of nearby Pasadena, Texas. "I kept that same approach, just like I do every other start, in the minor leagues."
Clemens is due to make his return start at Minute Maid Park on June 22, but manager Phil Garner likes what he's seen lately from his staff without the Rocket. On Tuesday night, three pitchers combined to scatter seven hits in a 4-1 victory.
"One of our biggest problems is we've not been able to establish that flow in a game," Garner said. "The last couple nights, that's more the flow we like to see."
Sampson was called up from Triple-A Round Rock on June 2 and made his major-league debut later that day, allowing six hits and three runs in 5 1/3 innings of relief against the Cincinnati Reds.
With Roy Oswalt nursing a sore back, Garner decided to start Sampson, who was 7-1 with a 2.79 ERA in 10 starts this season with Round Rock.
Sampson (1-0) said he had about 100 friends and family in the stands Wednesday and he put on a show, outdueling Cubs rookie starter Sean Marshall (3-4).
Of the 21 batters Sampson retired, 16 grounded out. He didn't have any strikeouts but assisted on six putouts.
"He was very much in control, very composed," catcher Brad Ausmus said. "He seems to be the type of guy who enjoys the energy of being on the mound."
Ausmus, batting .321 since April 13, led off the third with a long homer off that bounced off the brick facade in left field, his first. Outside of that mistake, Marshall was just as sharp as Sampson, striking out Morgan Ensberg and Preston Wilson to end the fourth.
John Mabry reached on an infield single in the fifth for the Cubs' first hit.
Jason Lane led off the bottom half with a deep fly that sailed just outside the left-field foul pole. Umpire Jim Reynolds called it a home run at first and a cannon blast echoed through Minute Maid Park as Cubs manager Dusty Baker jogged out to protest. Umpires Tim Welke and Kerwin Danley conferred with Reynolds and the ball was ruled foul.
Lane eventually walked, but Marshall struck out Ausmus and Adam Everett rolled into a double play.
"He was keeping us in the game, doing his job," Baker said of Marshall. "If you pitch like that every time, you're going to win a lot of ballgames."
Marshall has tossed at least seven innings in three starts this season and is tied with Pittsburgh's Paul Maholm for most starts by an NL rookie (12).
"Great effort by him," Baker said. "You just don't think you're going to lose a game 1-0."
Barrett led off the seventh with a single to center, the first ball a Cub hit to the outfield since the fourth. With two outs, Mabry lined a single to right, but Matt Murton flew out to Lane and Sampson smacked his glove with satisfaction.
"He did a real nice job," Ausmus said. "He didn't seem to be overmatched mentally or physically."
Marshall allowed four hits in seven innings. He struck out five and walked three and got a quick pep talk from Cubs ace Greg Maddux after the game.
"The guys who bounce back from losses the best, stay around the longest," Marshall said Maddux told him. "It's unfortunate to get a loss in a game like this, but that's just baseball."
The Astros took two of three from the Cubs, Houston's first series win since May 19-21. ... Center fielder Chris Burke left the game in the third inning when he re-separated his left shoulder whiffing on a pitch. Willy Taveras replaced Burke, who had started 11 of the last 13 games. Burke hurt his shoulder the first time when he crashed into the wall at Coors Field on May 6. He was placed on the disabled list and missed 13 games. After the game, Garner said Burke was day-to-day. ... The Cubs have won the season series with the Astros the past three years.