CHESTER, Pa. – A couple of hours before the Philadelphia Union’s 2016 home opener vs. the New England Revolution kicked off, Rob and Candy Rosenberry sat at a table outside Talen Energy Stadium, trying to imagine what it would be like once they stepped inside.

Perhaps they should have had an idea. Their son Keegan, after all, had already played in the same stadium with the Union academy and also in the Big East Championship with Georgetown. And just two weeks earlier, they made the spontaneous decision to fly to Texas to watch Keegan’s MLS debut – a 2-0 Philadelphia loss to FC Dallas.

But as fans began filling up the surrounding parking lots and pregame music blared behind them, the Rosenberrys shook their heads in unison when asked to envision their reaction when Keegan walked out of the Talen Energy Stadium tunnel for the first time as a professional soccer player – after many years rooting for the Union and playing for the club’s youth academy.

“It’s just…amazing,” Rob said, pausing as he searched for the right words. “Since he was drafted, I just can’t stop shaking my head thinking about how this has all evolved and how fortunate he is to be right here in his own backyard. And now to have the home opener where everyone’s so supportive – that’s special.”

It probably would have still been special if Keegan dressed and didn’t play. Or even if he started and flew under the radar. What happened next made it even more remarkable for Rosenberry’s parents – and all of his other family members, friends and former coaches that made the trip to the stadium in Chester – as the rookie right back played a starring role in the Union’s surprising 3-0 dismantling of the Revs.

Showing maturity that belies his age, and confidence on the ball that gave Philly an extra offensive punch on the right wing, the 22-year-old looked like one of the best players on the field, later being named to the MLS Team of the Week.

“It was definitely everything I hoped for,” Keegan told MLSsoccer.com from the locker room after the game. “I think the biggest thing for me was trying to handle all the nerves, combined with playing in front of all of your friends and family, as well as it being the first home game. But it was very exciting.”

Home openers, of course, are exciting for everyone, especially those that end in three-goal victories. But there’s no denying they carry extra meaning for hometown kids. Northeast Philly’s own John McCarthy had a very emotional one last season; a few years before that, Zach Pfeffer (now with the Colorado Rapids) had his while attending a high school 40 miles away.

For Rosenberry, who grew up about an hour away in Ronks, Pennsylvania, and played his high-school ball at Lancaster Mennonite, perhaps the coolest part was getting to hear the crowd react to the famous “Doop” song – the same one he used to get up on his feet for as a fan.

“For us to hear it three times in a game, that’s pretty awesome, especially after hearing it before and being in the stands,” he said. “It’s special to go from the outside looking in to the inside looking out. It’s pretty surreal.”

After the game, Keegan returned to the stands to share some embraces with all of his family members that braved the cold to be there for the occasion.

Some came further than others, like his uncle Doug Hershey, who drove four hours across the state and gushed at halftime about how well Keegan was “controlling the ball and distributing it to the open guys.” But, he added, “I was hoping it would be a little warmer.” Others didn’t let the cold stop them from sufficiently going nuts when Keegan made a beautiful backheel pass to catch Ilsinho in stride in the first half.

“Oh yeah, we were jumping out of our seats,” said Benji Kennel, a close friend of Rosenberry's from high school who went on to play soccer for Division III Messiah College.

“We wanted him to take the penalty kick at the end,” he added with a laugh.

Rosenberry, of course, is not quite at the level of being the team’s first-choice PK taker. But through three games, he’s not only emerged as one of the league’s top rookies but also, perhaps, a key component of a winning team as the Union have moved past the awful starts that doomed their 2014 and 2015 campaigns to win two of their first three contests.

For those that know him best, that’s not a huge surprise. Rosenberry has been a winner most of his life, playing for national championships at the youth club level, winning a state championship in high school and playing in the NCAA title game in his first season at Georgetown.

And he’s always wanted to play for his hometown franchise, especially after honing relationships with head coach Jim Curtin and other members of the staff while playing for the Union academy and the club’s PDL affiliate, Reading United.

His journey to the pros, though, was still a circuitous one.

Rosenberry was denied Homegrown status, even after writing a letter to the league and his father saying that “everyone tried as hard as they could to make the Homegrown thing work.” That led to the Union drafting him with the No. 3 overall pick – a move that surprised some pundits that had him going lower but, so far, looks to be a fortuitous decision.

It also made Sunday’s home opener feel even more gratifying, with his dad remarking that “so many things have fallen into place for Keegan.”

“He’s been dreaming of being a professional soccer player since I can remember,” Candy said before Sunday’s game. “I remember him writing a paper on it in the fourth grade. We never thought it was out of reach for him. It was just watching him chase it down. I think in the back of our mind, we thought he’d be here some day because he has that type of personality and work ethic.”

His parents have certainly seen that in him for over 20 years. His first pair of shoes as a baby were adidas Sambas, which today he has hanging from his car’s rearview mirror. Once, when Keegan was 6, his father – who was a Division III All-American at Messiah College and coached his son’s teams – remembers him getting an extra burst of energy when the ref said there were 30 seconds left and scoring the game-winning goal. A couple of years later, Keegan was so excited to tell his dad he juggled the ball 100 times in a row for the first time.

“With each stage,” Rob said, “he always wanted to beat whatever he did the day before.”

“And it just keeps getting better,” Candy added.

Rob glanced up at the professional stadium in front of them, smiling in agreement.

“You can’t beat this.”

Dave Zeitlin covers the Union for MLSsoccer.com. Email him at djzeitlin@gmail.com.