PHILADELPHIA -- The Cubs played nearly perfect baseball for seven innings on Thursday, only to watch yet another road game slip away in arguably the club's worst inning of the season.

Bryce Harper hit a walk-off grand slam off Derek Holland to cap a six-run ninth inning in Chicago's 7-5 loss at Citizens Bank Park. The shocking defeat came after starter Yu Darvish struck out 10 over seven scoreless frames and turned the game over to the Cubs' banged-up bullpen with a 5-0 lead in the eighth.

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Four Chicago relievers combined to allow seven runs while recording just four outs, as the Cubs were swept out of Philadelphia to fall to 23-38 on the road this season. It was the first time the Cubs lost on a walk-off slam in almost eight years to the date; the last came on Aug. 16, 2011, when Carlos Marmol served up a game-winner to Houston's Brian Bogusevic.

"That¡¯s No. 1," Anthony Rizzo said when asked where this loss ranks.

¡°It sucks. It just sucks," said an almost speechless David Bote.

"That one¡¯s gonna leave a mark," manager Joe Maddon admitted.

So how did it all go so wrong, so quickly?

For starters, Maddon said Darvish was done after throwing 92 pitches over seven innings. Though he had struck out 10 and walked zero, Darvish admitted he had started to lose his command said it was a "good decision for the team."

Fast forward to the ninth. With the Cubs leading 5-1, Rowan Wick quickly retired the leadoff hitter before Cesar Hernandez chopped a ball to shortstop. Instead of picking up the second out, however, Bote -- filling in for Javier Baez, who was scratched due to an illness -- bobbled it and couldn't recover in time.

Wick then allowed back-to-back singles before handing the ball to Pedro Strop, who allowed a third straight hit, then plunked Rhys Hoskins to load the bases with one out and Chicago clinging to a 5-3 lead.

With Craig Kimbrel, Steve Cishek and Brandon Kintzler all on the injured list, Maddon called on Holland to face the left-handed hitting Harper.

"That¡¯s not an excuse though. You can¡¯t use that," said Holland, whose 2-2 pitch inside off the plate to Harper ended up in the second-deck in right field. "I¡¯ve been in these situations before. I¡¯ve come out of the ¡®pen before. So you can¡¯t use that as an excuse. There¡¯s nothing I can really say. I made the pitch I wanted to make. ¡­ At the end of the day, no matter what, you¡¯ve got to give the guy credit."

Maddon admitted that it was as difficult of a spot as possible for Holland, while also pointing to a trio of plays before the grand slam. Along with the Bote error, two of the three ninth-inning singles deflected off the glove of second baseman Ian Happ before finding their way into center field.

¡°You look at the bullpen, but there¡¯s plays that we could have made also," Maddon said. "When we win, we win as a team. When we lose, we lose as a team. There¡¯s no blame. We lost."

That's been the story far too often anytime the Cubs get on a plane this season. While they remain tied with the Cardinals atop the National League Central despite the loss, history suggests Chicago will need to improve upon its 23-38 (.377) road record down the stretch.

Only one team in Major League history has even qualified for the postseason with a sub-.400 winning percentage away from home. That team was the 1987 Twins, who went just 29-52 on the road compared to 56-25 at home. While some may be quick to point out that those Twins went on to win the World Series, they did so by going 4-0 at home and 0-3 on the road during the Fall Classic.

That almost certainly won't be an option for a Cubs team that is very unlikely to have home-field advantage even if it makes a run to the World Series. Even the Rays, who currently hold the final AL Wild Card spot, are 6 1/2 games better than Chicago.

"I mean with the road struggles, being able to win a game here would have been nice before going to Pittsburgh," Rizzo said. "But we didn¡¯t. It¡¯s definitely tougher at this part of the season than April or May when this happens."

Following the loss, the Cubs boarded a plane to travel across the state of Pennsylvania, where they will attempt to win their first road series since May 17-19. Reinforcements could soon be on the way with Chicago expected to activate Kintzler on Friday, while Kimbrel may not be far behind. Cishek is eyeing a Tuesday return.

Regardless of who is or is not available, the Cubs know they need to start winning games -- especially outside of the Friendly Confines.

"This is our full team. Whoever's on this roster is our full team," Rizzo said. "... We can¡¯t hang our heads too long, because we¡¯ve got a game tomorrow. That¡¯s the beauty of baseball is when things like this happen you can get out there tomorrow and just go play again."