PHILADELPHIA — In the third inning of Saturday’s defeat, Guardians leadoff hitter Steven Kwan skied a ball to deep center field at Citizens Bank Park. Phillies center fielder Brandon Marsh plucked it from the sky above the wall’s 401-foot sign. It wasn’t a clear-cut robbery, but Kwan certainly would’ve had extra bases — and maybe more — if Marsh hadn’t been there.

Asked later if he thought he missed a home run, Kwan didn’t bat an eye.

“No,” he said. “I don’t hit very many home runs to center, so I’ve been hedging myself for a good amount of time.”

There was no such confusion a day later, when Kwan lifted the Guardians to a 4-3 series-clinching victory over the Phillies on Sunday afternoon with a no-doubter in the seventh inning. Kwan’s solo homer, on a 98.3 mph sinker bearing off the plate inside against left-hander José Alvarado, and the club’s lockdown bullpen ensured Cleveland overcame No. 10 prospect Joey Cantillo’s shaky MLB debut to take two of three from the National League’s top team.

“It was huge,” manager Stephen Vogt said. “That game could’ve easily gotten away from us, and Kwan came up with a huge swing. Home runs help. It’s not [a big] part of who we are, necessarily, but we have been able to hit some in big moments.”

As speculation swirled about how active Cleveland will be at the upcoming Trade Deadline on Tuesday, the club’s strengths and weaknesses were on full display this weekend in the City of Brotherly Love. It rode a strong Ben Lively to victory in Friday’s opener but dropped a laugher behind Carlos Carrasco on Saturday. Then in Sunday’s rubber game, another big performance by their MLB-best ‘pen underscored why the Guardians (63-42) sport the American League’s best record as the calendar creeps toward August.

“[Our kind of bullpen] is super rare,” Kwan said. “Top to bottom, different arm slots, different angles, different velocities, left, right. It’s a lot of fun [to play behind them].”

Summoned from Triple-A Columbus to fill Cleveland’s revolving door of a fifth rotation spot, the 24-year-old Cantillo allowed a leadoff homer to his first batter, Kyle Schwarber, and coughed up another homer to Schwarber in the third. The left-hander exited after 3 1/3 innings, allowing those three runs while also walking and striking out three apiece.

But the Guardians’ pen is so airtight it can keep them in pretty much every game if they find a way to score enough runs. Jhonkensy Noel made sure they did with a Statcast-projected 436-foot three-run homer in the fourth, and Cade Smith, Nick Sandlin and Tim Herrin kept the game tied until Kwan’s go-ahead jack in the seventh.

Hunter Gaddis, Scott Barlow and Emmanuel Clase then combined to lock down the final nine outs. Guardians relievers allowed only three baserunners after the fourth inning.

Clase needed seven pitches to record his MLB-leading 33rd save.

The numbers for Cleveland’s pen are starting to get mind-boggling. Of the group that pitched Sunday, Sandlin’s 3.86 season ERA is the highest. Smith, Herrin and Gaddis all sport ERAs under 2.00, and Clase’s is a minuscule 0.73.

“It’s absolutely amazing,” Gaddis said of Clase. “That dude is awesome. What he can do with a baseball is incredible.”

All told, the Guardians’ bullpen leads MLB in ERA (2.47), WHIP (1.04), opponents’ average (.199), and ranks second in K-BB ratio (3.28), third in strikeouts (427) and third in K/9 (9.66). Its bullpen ERA is more than a full run better than the next American League team, the A’s (3.54).

“When they do give up runs, we’re like, ‘What happened?’” Vogt said. “They’ve just been so good in every situation no matter who they’re facing. It’s such a blessing to have so many guys down there that we trust in any situation.”

Asked if he ever expects the bullpen to be less than perfect, Noel shook his head.

“We have the best bullpen in the league,” he said, through team interpreter Agustin Rivero. “So I never expect for that to happen.”