The surging Cubs look to continue their dominance of the lowly Pirates on Monday night in the opener of a three-game set at PNC Park.Chicago (80-50) -- owner of the NL's best record -- became the first team in the majors to 80 wins after beating Washington 6-1 on Sunday. The Cubs took two of three from the Nationals, winning an eighth consecutive series for the first time since May 28-June 24, 1937.Rich Harden equaled a career high with 11 strikeouts and Mark DeRosa became the first Cubs player to homer in four straight games since Fred McGriff (Sept. 20-23, 2001) as Chicago wrapped up a 4-2 homestand and improved to 21-8 since July 27.Geovany Soto and Kosuke Fukudome also went deep for the Cubs, who moved 30 games over .500 for the first time since finishing 96-65 in 1984."We're playing good baseball, but again, we just have to keep going. Can't sit," manager Lou Piniella told the Cubs' official Web site.If recent history is any indication, Piniella's club will be able to keep things going with a matchup against Pittsburgh (57-73). Chicago is 11-4 in the 2008 series and has won 14 of the last 18 meetings.The Cubs might also benefit from another strong effort from DeRosa, who has hit .383 (18-for-47) with six homers and 14 RBIs over his last 14 games.However, it is unclear if first baseman Derrek Lee will be in the starting lineup Monday after he sat out Sunday due to lingering back spasms.With or without Lee, the Cubs are set for a brief stop in Pittsburgh before starting a seven-game homestand Thursday against Philadelphia. They'll likely be fine away from Chicago as they've won 10 of their last 11 road contests.The Cubs send Ted Lilly (12-7, 4.25 ERA) to the mound as he tries to bounce back from his first loss since the All-Star break.The left-hander held Cincinnati hitless through the first five innings before suffering a 2-1 home defeat on Wednesday. He gave up two runs and two hits, while fanning seven in seven innings.Lilly hasn't received a decision but has compiled an 8.38 ERA in two starts at Pittsburgh this season. He also held the Pirates to a run and six hits in 6 1-3 innings of a 5-1 home victory on Aug. 2 to improve to 2-0 with a 4.74 ERA in eight lifetime games against them.Pittsburgh concluded a 1-4 road trip Sunday at Milwaukee, and was unable to avoid a three-game sweep after falling 4-3 in 12 innings. The Pirates stranded 14 and went 3-for-13 with runners in scoring position."Both sides left a lot of guys on base, a lot of hits, we just couldn't come up with the big one," said Pirates manager John Russell, who was ejected along with first baseman Adam LaRoche in the middle of the sixth inning for arguing balls and strikes.Pittsburgh tries to turn things around in the opener of a six-game homestand behind Jeff Karstens (2-2, 2.25), whose outing was pushed back two days to accommodate the return of starter Tom Gorzelanny.The right-hander lost a second straight start on Aug. 17, allowing four runs and nine hits in six innings of a 4-0 home loss to the New York Mets.Karstens, though, hopes to repeat his performance against the Cubs from Aug. 1, when he scattered five hits in six innings of a 3-0 win at Chicago.