Neither is certain anymore as the struggling clubs conclude their seasons with a three-game set beginning Monday night at Turner Field.Atlanta (89-70) led St. Louis by 8 1/2 games through Sept. 1, and it appeared to be only a matter of time before it clinched its second consecutive wild-card berth.The lead, however, is now down to a single game after the Braves' 3-0 loss in Washington and the Cardinals' 3-2 win over the Chicago Cubs on Sunday. St. Louis finishes with a three-game series at major league-worst Houston."This was a very brutal loss for us," first baseman Freddie Freeman said.The Braves have lost five of seven, scoring one run or fewer in each of their last three defeats. Atlanta mustered only four hits Sunday, with No. 1-4 hitters Michael Bourn, Martin Prado, Chipper Jones and Dan Uggla each going 0 for 4."We know what's at stake. We know what every game means," manager Fredi Gonzalez said. "You've got to go out and play the game with some fun. We can't play with white knuckles on the bat and hold the ball so hard you can't throw it."The Phillies have seemed pretty tense themselves despite having wrapped up their fifth straight division title more than a week ago.Philadelphia (99-60) avoided a ninth straight loss with Sunday's 9-4 win over the New York Mets, ending the longest losing streak for any team clinching first place since the inception of the World Series in 1903.Another victory would give Philadelphia its third 100-win season in the franchise's 129-year history. It had back-to-back 101-win seasons in 1976 and 1977.The Phillies were outscored 37-16 during their skid but busted out of their slump with the help of Hunter Pence, who hit a two-run homer in the first inning before falling a double short of a cycle.They were playing with their full lineup for the first time since clinching the division Sept. 17, then manager Charlie Manuel promptly removed Ryan Howard and Jimmy Rollins in the fourth and sixth inning, respectively, with the game in hand."I think you see the difference. When you get all of our guys in there, we've got a pretty good lineup," Manuel said. "When you have two or three of them missing, we become a different team."Cliff Lee (16-8, 2.38 ERA) will take the mound Monday for his final start of the regular season.Lee is coming off his first loss since July 25, though he pitched just as well as he did when winning each of his seven decisions with a 1.00 ERA over nine starts from July 30-Sept. 15. The left-hander gave up three runs -- two earned -- with nine strikeouts over seven innings of a 3-0 loss to Washington on Tuesday.Lee beat Atlanta 9-0 on Sept. 5, pitching a five-hitter for his first victory in four starts against the Braves this season. He's 1-2 with a 3.29 ERA in those outings, and his only other career win versus Atlanta came on June 18, 2004, while pitching for Cleveland.He'll be opposed by rookie Randall Delgado (1-1, 2.70), who is coming off his first major league victory.Delgado allowed five hits in five innings of a 4-0 win over Florida, and Atlanta's four runs of support equaled the amount it provided him through his first five starts.The right-hander, though, has walked 10 over his last 20 innings, throwing 90-plus pitches through five innings in each of his last four outings.The Braves and Phillies have split the last 22 meetings at Turner Field.