PHILADELPHIA -- The battle for the National League pennant is down to the D-backs and Phillies -- and as we've seen so far in the 2023 postseason, it's impossible to predict playoff baseball.

Still, there are a few keys to this particular NL Championship Series matchup that should ultimately determine the outcome.

Obviously, winning any postseason series typically takes a complete team effort, especially in a best-of-seven showdown. That means production from up and down the lineup, solid defense around the diamond and quality pitching from both the rotation and the bullpen. Not to mention making all the right calls from the dugout if you're D-backs skipper Torey Lovullo or Phillies manager Rob Thomson.

All that said, let's take a closer look at the three areas that figure to have the largest impact on which team represents the NL in the World Series.

Which superstar shines brightest?
This postseason has seen some of the top teams from the regular season bow out early on the backs of subpar performances from some of their biggest stars.

Mookie Betts and Freddie Freeman combined to go 1-for-21 as the Dodgers were swept out of the NLDS by the D-backs. The Braves were eliminated by the Phils in an NLDS in which Ronald Acuña Jr. and Matt Olson were just 6-for-30 and did not hit a single home run after combining for 95 in the regular season.

The D-backs and Phillies, however, have not had that problem.

Arizona rookie sensation Corbin Carroll is 7-for-17 (.412) with two home runs, four RBIs, six walks, six runs, two stolen bases and a 1.389 OPS in his first five career postseason games.

• Carroll 'rising to the occasion' on postseason stage

Meanwhile, all Bryce Harper did against the rival Braves in the NLDS was go 6-for-13 with three home runs, five RBIs, five runs, one stolen base and a 1.765 OPS. Oh, and a pair of epic staredowns.

Now, each superstar player has had plenty of help. Gabriel Moreno (three homers, 1.107 OPS), Christian Walker (HR, 1.023 OPS) and Ketel Marte (two homers, .984 OPS) have each had a strong postseason for Arizona. For Philadelphia, Trea Turner (12-for-24, two homers and four stolen bases) and Nick Castellanos (back-to-back two-homer games to close out the NLDS) each have an OPS north of 1.400 through six games.

But when it comes to the biggest stage, one player has the potential to shift an entire series -- and nobody is more likely to do that for his particular club than either Carroll or Harper.

If one of those superstars puts his team on his back in the NLCS, watch out.

How will the rotations shake out?
These teams are very similar in that they have a pair of aces at the top of their rotations followed by some question marks. Each team has also had to use just three starters in the postseason to this point -- but they will need a fourth in the NLCS.

Game 1 will likely be a showdown between Zac Gallen and Zack Wheeler, each of whom was in the NL Cy Young conversation for much of the season. Next up, the D-backs figure to turn to Merrill Kelly (6 1/3 scoreless innings this postseason), while the Phils will almost certainly go with veteran Aaron Nola (1.42 ERA in two starts this postseason).

Gallen and Wheeler could then pitch Game 5 (if necessary) on normal rest, while Kelly and Nola would get an extra day before returning for Game 6. Thus, those four alone could determine the outcome of this series since they'll account for four of the possible seven games.

Game 3 (and possibly Game 7) could feature Brandon Pfaadt against Ranger Suárez, while both teams will likely have a starter making his 2023 postseason debut in Game 4.

Whether it be one team's aces carrying the load or those "other" guys stepping up, it should come as no surprise that these rotations will play a pivotal role in which team moves on.

Can D-backs overcome Phillies' home-field advantage?
Arizona has had little trouble playing on the road this postseason. The D-backs went into Milwaukee and swept the Brewers in the NL Wild Card Series, then outscored the Dodgers 15-4 in a pair of games at Dodger Stadium to begin the NLDS.

But Philadelphia is different.

Going back to last postseason, players from both the Phillies and other teams across the league have commented on the atmosphere at Citizens Bank Park. And it’s hard to argue, considering Philadelphia is 10-2 with a +40 run differential at home over the past two postseasons. That includes going 9-0 with a +39 run differential in all pre-World Series rounds.

“It can be deafening at times,” Thomson said. “And it creates a lot of energy for us, and sometimes it can create some intimidation to the opposition. So I think that's the biggest factor, no question about it.”

For the D-backs to win the pennant, they will need to steal at least one game in Philadelphia -- something the Braves, Marlins and Padres have all been unable to do over the last two postseasons.