(Sports Network) - The Houston Astros are caught in a four-game slide and will try to right the ship this afternoon in the finale of a three-game series against the Chicago Cubs at Minute Maid Park.

Houston suffered an 8-6, 18-inning loss on Tuesday night, as Matt Murton tied the game in the ninth for Chicago and drove in the winning runs in the 18th inning to lead the way.

Aubrey Huff went 3-for-5 with two RBI and Adam Everett and Orlando Palmeiro each drove in two runs for the Astros, who are now four games off the lead in the National League wild card race.

Roger Clemens started on the mound and gave up five runs on seven hits with a walk and five strikeouts in six innings. Dave Borowski was saddled with the loss after going six innings and being charged with two runs on four hits.

Houston center fielder Willy Taveras finished the game 1-for-9 and extended his hitting streak to 18 games, the longest current streak in the majors.

The Astros, who are 4-4 on a nine-game homestand and 34-30 at home this season, will send veteran Andy Pettitte to the mound on Wednesday and he is 11-12 with a 4.86 ERA in 27 games (26 starts) this season.

Pettitte has alternated wins and losses over his last seven starts and defeated San Diego the last time out on August 11. He yielded a pair of runs and three hits in seven innings.

The veteran lefty, who is 7-5 with a 4.42 ERA at home in 2006, owns a 2-1 mark with a 3.00 ERA in three starts against the Cubs this season. He pitched seven innings of one-run ball on June 13, then defeated Chicago on July 4, allowing a run on six innings. He lost to the Cubs on July 20 after giving up four runs and six hits in five innings of work.

In nine career games against the Cubs, Pettitte is 2-3 with a 3.88 ERA.

Meanwhile, Chicago has won three in a row after a four-game losing streak. Last night Murton was the hero and finished 2-for-5 with three RBI, while Jacque Jones went 2-for-7 with a three-run homer and two runs scored.

Rich Hill, who came into the game in the 17th inning, retired the Astros in order in the 18th frame to finish the marathon game.

Hill was originally slated to start this afternoon's contest. The Cubs will instead turn to rookie Ryan O'Malley, who will be called up from Triple-A Iowa to make his major-league debut.

O'Malley, an 26-year-old who joined the Chicago organization as an undrafted free agent in 2002, has posted a 7-7 record with a 4.08 ERA in 26 games (19 starts) at Iowa this season.

Chicago improved to 4-4 on a nine-game road trip and 26-37 away from Wrigley Field this season.

The Cubs have won five of their last six over the Astros, who are 8-6 against Chicago this season. The Cubs won last year's season series by a 9-7 margin.