Expect the unexpected. That’s the theme of this fall’s thrilling baseball postseason, as we’ve witnessed shocking upsets, dramatic extra-innings affairs and unsung heroes playing pivotal roles.

What can fans expect in the National League Championship Series? Likely more of the same, which is great news as we inch closer to the Fall Classic.

The NLCS will feature none of the top four seeds, as the fifth-seeded San Diego Padres face the sixth-seeded Philadelphia Phillies following a pair of surprising series victories by both clubs.

In what promises to be a memorable NLCS between two underdogs with hungry fan bases, here are five storylines to watch ahead of Game 1 on Tuesday night in San Diego:

REST: Both clubs won their NL Division Series in four games, so they are rested and ready to go. San Diego’s Yu Darvish, who would have started Game 5 against the Los Angeles Dodgers on short rest if that series had gone the distance, will get the nod in the opener. Blake Snell and Joe Musgrove are lined up to start the following two games, putting the Padres in an enviable position.

Opposing Darvish will be Zack Wheeler, who might have taken the mound in Game 5 if the Atlanta Braves had extended the NLDS. Aaron Nola seems likely to start Game 2, meaning Wheeler and Nola could make two starts if the NLCS goes the distance. That bodes well for the Phillies.

HOME FIELD: In their first NLCS in 24 years, the Padres will host the first two games (and last two, if necessary) in front of an energized, raucous crowd eager to root the 53-year-old club on to its first World Series appearance since 1998.

San Diego has more road wins (48 including the postseason) than home wins (46), but in the NLDS — the first playoff series in front of fans in Petco Park since 2006 — the crowd was a factor in eliminating the rival Dodgers. If the series goes to Game 6 or 7 in San Diego, the advantage would clearly be on the Padres’ side.

STAR POWER: The series features no shortage of marquee names, headlined by superstars and former Washington Nationals teammates Bryce Harper and Juan Soto. It’s also a matchup of two of the sport’s highest-paid players, as Harper (13 years, $330 million) and Manny Machado (10 years, $300 million) are raking in the dough.

Harper enters the NLCS on a roll, as he is 10-for-23 (.435) with six extra-base hits and a 1.437 OPS in the playoffs. Machado (.296, two HRs, five RBIs, .980 OPS in the postseason) also has excelled in October, but Soto (.250, one extra-base hit, three RBIs, .586 OPS) has yet to click on offense. If the Padres are to advance, a return to form from the young superstar would take the pressure off Machado and his teammates.

BULLPEN: The Padres have a clear advantage with elite closer Josh Hader, who electrified the Petco Park crowd with three consecutive strikeouts to eliminate the Dodgers in Game 4. Hader scuffled when he first came over from the Brewers in a trade, but he has regained his dominant All-Star form and could be the difference between the Padres advancing or going home.

While the Phillies don’t have a reliever with Hader’s pedigree, their oft-maligned bullpen has excelled lately. Seranthony Dominguez, who has thrown 3 2/3 scoreless postseason innings, and Jose Alvarado, who has a 2.09 ERA in 47 games (including the postseason) since he was recalled from the minors on June 12, will be relied on heavily in high-leverage situations.

MANAGERS: Rob Thomson took over for the fired Joe Girardi in early June and turned the Phillies’ season around in historic fashion. He’s the first manager in major league history to inherit a team at least seven games under .500 and win a postseason series. Will his lack of experience cost his team? It hasn’t yet, so there’s little reason to expect it will.

Bob Melvin, meanwhile, is a much more experienced skipper and is back in a league championship series for the first time since he guided the Arizona Diamondbacks in 2007. In his first season with San Diego, Melvin is trying to reach the World Series for the first time in nearly two decades as a manager.

–Liam Fitzgerald, Field Level Media