As Donald Trump was celebrating his epic New York victory last Tuesday night -- once again in the glow of the media spotlight -- Sen. Ted Cruz was toiling away in Philadelphia, meeting in a private room with potential delegates for about an hour after delivering a little-noticed speech on unity.

The symbolism was not lost on Cruz’s Pennsylvania chairman Lowman Henry, who says he attended all of Cruz’s delegate meetings during the candidate’s swing through the Keystone State.   

“I would characterize that as a microcosm of this entire campaign,” Henry told Fox News.  “He's willing to roll up his sleeves and go out there and do the hard grass-roots work that is necessary to win delegates.” 

The meeting in Philadelphia was one of many Cruz held with dozens of delegate candidates in a state where voters will select three delegates per congressional district Tuesday. He has hosted them on his campaign bus, backstage at campaign events and, in Scranton, Cruz met with a group in a kitchen at the Radisson hotel after a rally. 

Fifty-four delegates from the state’s 18 congressional districts will go to the Republican National Convention unbound.  But even as he’s poised to lose Pennsylvania’s popular vote, Cruz’s team worked hard to field a slate of known supporters in an attempt to pick off delegates likely to remain loyal to him at the convention. In robo-calls, direct mail and at rallies, his campaign has promoted pro-Cruz candidates, many whose names would otherwise be unrecognizable to voters.

“There will be no direction on the ballot as to who those delegate candidates support,” Henry said.  “So we are working hard to make sure that the voters who we have identified as Cruz supporters know who our delegate candidates are.”

“I didn’t even realize there was delegates being elected,” said Harold Clark, Jr., a voter attending a Cruz rally in Williamsport, Pa., last week. Clark only found out about the delegate portion of the ballot after his father told him that morning.  

“I would be caught blindsided,” Clark said after a pro-Cruz delegate candidate handed him campaign material. “I’ll tell everyone I know and pass the word, because I didn’t know anything about it.”

Trump, positioned for a decisive Pennsylvania victory, fielded his own delegate slate. But a Fox News producer who covers the Trump campaign reported only one instance of delegate cards being passed out at Trump rallies.

Aides to Trump told Fox News that until recently, the front-runner was unaware of the critical difference between delegate allocation and delegate selection. 

On Monday, however, the candidate himself held up a card at his rally in West Chester, Pa. 

"We have a slate of people,” Trump told voters. “Go vote for the slate." The list is also now available on Trump’s Twitter feed and his website. His campaign also started placing robo-calls and sending emails, notifying voters of his slate.

As Trump attempts to ramp up his own delegate operation, he’s fired off a barrage of accusations that Cruz is “wining and dining” delegates to win them over.  Cruz mocked the notion at a Fox News Town Hall Sunday night.

“I was laughing at the Trump campaign claiming that we're wining and dining people,” Cruz said, recounting one of his delegate meetings in Pennsylvania.  “I said, ‘gosh, do you see any wine?’ We didn't even give them a glass of water.”

Fox News' Christopher Snyder and James Rosen contributed to this report. 

Dan Gallo is a Fox News Channel Field Producer based in Los Angeles. Follow him on Twitter: @DanGallo