ATLANTA -- The Braves kept their division title hopes alive and clinched the National League's top Wild Card entry on Wednesday.
Shortly after Atlanta claimed a 3-0 win over the Marlins, the Cardinals suffered a 2-0 loss to the Astros. The loss dropped the second-place Cardinals 6 1/2 games back in the NL Wild Card standings and reduced the front-running Braves' magic number to one.
But because the Braves won the season series against the Cardinals, they are guaranteed home-field advantage in the Oct. 5 one-game playoff that will be contested between the two Wild Card entrants. The only way the Braves will not play in this game is if they win the NL East.
Atlanta trails the Nationals by four games with seven games remaining. While the odds are steep, the club is still holding out hope it can win the division and avoid the dangerous one-game playoff that will determine which Wild Card entry advances to the NL Division Series.
"It's a fun part of the year," Braves manager Fredi Gonzalez said. "It's going to be a difficult task, but it can be done. We need some help. We just got to take care of ourselves and win."
Thursday's key games to watch (all times ET)
Marlins (Turner, 2-4) at Braves (Hanson, 12-9), 7:10 p.m. Preview >
Nationals (Gonzalez, 20-8) at Phillies (Cloyd, 2-1), 7:05 p.m. Preview >
If the postseason started today ...
This is how the teams would match up: Postseason Bracket »
To calculate a team's magic number, take the number of games it has remaining and add one. Then subtract the difference in the number of losses between that team and its closest pursuer.
A tiebreaker game will be played to determine a division winner, even if the tied clubs are assured of participating in the postseason. If a division championship tiebreaker is necessary, the head-to-head record between the clubs will determine home-field advantage. If the head-to-head record is tied, then the division record will be the next tiebreaker.
If two clubs are tied for the two Wild Card berths, home-field advantage will be determined by the head-to-head record between the clubs. If the head-to-head record is tied, then the division record will be the next tiebreaker.
Tiebreaker rules »
2012 postseason schedule
Wild Card playoff games: Oct. 5
Division Series: Oct. 6-12
AL Championship Series: Oct. 13-21
NL Championship Series: Oct. 14-22
World Series: Oct. 24-Nov. 1
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.