The Cardinals are 2 1/2 games behind the Pirates, while the Reds came out of an 11-game road trip to end the first half one game out of first place.
"I think every team holds their own destiny, and that's exactly where we are," Matheny said. "You can see pieces coming together as well as every other team. I think we're moving forward."
Adam Wainwright will get the start for the Cardinals to begin the second half after allowing one run on eight hits over six innings against the Rockies in his last outing on July 4. Wainwright stranded six runners in that game, which followed an outing in which he gave up seven runs on 11 hits in five innings against the Pirates.
"The difference in a great outing and a bad outing, really, is just pitches in a jam at certain times in a game with two outs," Wainwright said.
Wainwright will be tasked with maintaining the momentum from a 5-4 walk-off win against the Marlins, and he'll face Reds starter Mat Latos, after the team decided not to re-arrange the order and have ace Johnny Cueto open the second half as was previously considered.
Mike Leake, Cueto, Bronson Arroyo and Homer Bailey will follow Latos in that order, which Reds manager Dusty Baker and pitching coaches Bryan Price and Mack Jenkins found was the best way to give their pitchers an equal amount of days off between starts.
"We debated having Cueto start the first game, but everybody else would have had a couple of extra days off and that would have been on his regular turn," Baker said.
Reds: Rolen's return creates dilemma
Scott Rolen returned to the Reds' lineup for Sunday's first-half finale against the Padres, replacing hot-hitting rookie Todd Frazier at third base. Baker is now left with having to decide between the veteran Rolen or 26-year-old Frazier in the lineup.
"I don't want to have to be answering this every day about Scotty and Frazier and who's playing and who's not playing," Baker said. "From now on, it's 'manager's decision,' like basketball. It's easier. I don't know what I am going to do, but I will figure it out.
Rolen went 0-for-4 with three strikeouts in Sunday's 4-2 win against the Padres, and is batting .178 this season.
Cardinals: Tough losses coming in close margins
Sunday's 5-4 walk-off win against the Marlins improved the Cardinals' subpar record in close games. The team ended up being 10-14 in one-run games and 4-7 in two-run games before the All-Star break, and Matheny is hoping that Sunday's win is just the beginning of the close games falling in the Cardinals' favor.
"We've had so many close games that we easily could have and should have won, and didn't," Matheny said. "To me, those are going to stack up. I just think so. We all have to do our part to make those things happen. It's not just going to happen automatically. Our record could be so different right now, and there's not a lot of teams that could say that."
The two squads have played a pair of three-game series already this season, with the Cardinals winning four of six.