(Sports Network) - A pair of National League divisional front-runners get together for a potential playoff preview tonight when the Central-leading Cincinnati Reds host the East-leading Atlanta Braves in the first of three at Great American Ball Park.

The Reds hold a half-game edge on the St. Louis Cardinals in the Central after taking two of three games from Milwaukee in a series that ended with a 10-2 Reds win on Wednesday.

The Braves, meanwhile, are 2 1/2 games up on the streaking Philadelphia Phillies. Philadelphia has cut into the lead with an eight-game win streak while the Braves have dropped four of six, including a series finale to Washington Thursday.

Cincinnati sends emerging ace Johnny Cueto to the mound in the opener in search of fifth straight win and with a chance to equal his career high in victories. The third-year Dominican export improved to 10-2 on the season with eight innings of scoreless four-hit ball in a 7-0 defeat of Houston on July 24.

The triumph lowered his earned run average to 3.18 and marked his sixth straight unbeaten start since a 1-0 loss at Seattle on June 18. His opposition batting average this season - .247 - is 12 points below his career clip and 15 points better than the .262 average he allowed last season.

For the Braves, right-hander Kris Medlen makes his second straight start after a trip to the bullpen and seeks his first win since July 7. A 24-year-old Californian, Medlen tossed six innings and allowed five runs on eight hits while getting a no-decision in Atlanta's 10-5 win at Florida on July 24.

It was his first game-opening assignment after four straight trips from the bullpen, during which he allowed six hits and four runs across five innings between July 11 and 21.

The former 10th round draft pick - 2006 - is 4-1 in 15 road games this season with a 4.05 ERA in 53 1/3 innings.

He has never faced the Reds.

On Thursday, Ian Desmond and Adam Dunn each homered, as the Nationals edged the Braves, 5-3, in the rubber match of a three-game series.

Derek Lowe (10-9) took the loss after allowing four runs on five hits in five innings. Matt Diaz hit a two-run homer for the Braves.

On Wednesday, Brandon Phillips hit his fourth career grand slam while Joey Votto went 3-for-5 with a home run, powering the Reds to a 10-2 victory over Milwaukee.

Phillips, who had two hits, slugged his first grand slam since 2007. Miguel Cairo went 2-for-4 with a walk and two RBI for the Reds, who went 4-2 on their road trip.

Cincinnati scored its runs in bursts, plating five in the sixth and eighth innings. Rookie Travis Wood (1-1) benefited from the first surge, getting his first major league win after allowing two runs in five innings. He gave up five hits, walked one and struck out six.

Atlanta swept a two-game set from the Reds earlier in the year after the Reds won six of the nine matchups in 2009.

07/30 11:21:45 ET