The USL’s Eastern Conference has its share of historic rivalries, and the Keystone Derby between the Pittsburgh Riverhounds and Harrisburg City Islanders ranks among the top tier. This Saturday, the rivalry resumes when Pittsburgh hosts Harrisburg at Highmark Stadium (7 p.m. ET | Match Center).

The annual clash has generated so much added intrigue that it has now garnered sponsorship, with this year’s series presented by K&L Gates and the Pennsylvania Lottery.

The first stop is at Highmark, which debuted in 2013 and coincidentally featured a Keystone matchup. Here is a look back at some of the noteworthy matches that City Islanders and Riverhounds fans have been treated to over the years at Pittsburgh’s home venue over the previous three seasons:

ISLES SPOIL HOUNDS’ HOME DEBUT: April 13, 2013 – Harrisburg 2, Pittsburgh 1: The Riverhounds had a sellout crowd and a second-half lead during their first match at the soccer-specific Highmark Stadium. Jose Angulo etched his name as the first goal-scorer in the venue’s history with a second-half header. But what had been a jubilant undertaking for the host Hounds slowly dwindled down the stretch.

Sainey Touray rushed into the box to slot home a low finish in the 77th minute off of a Jamiel Hardware assist to tie the score. Then Harrisburg grabbed the lead in the final minute of regulation. Pittsburgh was unable to clear the ball from its defensive end, and the City Islanders’ Cris Hernandez – on loan from the Philadelphia Union – crossed to Lucky Mkosana, who finished from six yards out for the road victory. The fact that Mkosana had not even been with the club in training made his game-winning accomplishment more remarkable.

“Lucky’s not trained with us yet, but he shows up at the bus and gets the game-winner,” City Islanders Head Coach Bill Becher said to Penn Live. “We know the quality’s there, and he’s been training with Columbus, so his fitness is there. He came in and did his job.”

SECOND-HALF BARRAGE: June 11, 2014 – Harrisburg 3, Pittsburgh 1: The Wednesday night matchup featured two sides in dire need of a win. Harrisburg had two victories through 10 games and Pittsburgh only had one win through 11. The Riverhounds, more so, needed a jumpstart as Head Coach Justin Evans had been dismissed earlier in the season following a 0-4-3 start.

The match was delayed because of rain for 45 minutes and shortly after kickoff, host Pittsburgh grabbed the lead in the seventh minute off the foot of former Fulham striker Collins John. It stayed that way through the first half, but then Harrisburg’s offense woke up on the other side of the break.

Jimmy McLaughlin’s 46th-minute penalty kick was saved by Michael Lisch, but the rebound went directly back to McLaughlin for an easy tap-in to tie the score at 1-1. Clesio Bauque gave the City Islanders a 2-1 lead in the 63rd minute with a shot from outside the box. And for good measure, Yann Ekra was just able to notch his 82nd-minute goal as Riverhounds goalkeeper Michael Lisch partially stopped the shot, only for it to slip between his legs.

“We understand we’re in a process with the new coaching staff, but at the same time, we need results. We need points,” Pittsburgh defender Andrew Marshall said to Trib Total Media. “More than anything, our fans deserve a home win – multiple home wins – and it just wasn’t good enough from us.”

KERR & VINCENT SHOW: March 28, 2015 – Pittsburgh 5, Harrisburg 2: The Riverhounds’ home opener was emblematic of the club’s two key contributors for the duration of the 2015 season. Following Rob Vincent’s fifth-minute goal, off his own rebound, the end result never really was in doubt as Vincent would record a brace and assist two of Kevin Kerr’s three goals that day.

Under the guidance of new Head Coach Mark Steffens, Kerr and Vincent did all the legwork, and the second half really pushed the boundaries. Kerr’s second goal in the 52nd minute was rocketed into the left side of the frame. In second-half stoppage time, Vincent’s second tally almost came from the same location as Kerr’s second tally as Vincent placed it perfectly into the left-side netting.

“Except for the 18-degree temperatures, the atmosphere was great,” Steffens said to Trib Total Media. “Getting a win by any score is good. I couldn’t have scripted it any better.”

STOPPAGE-TIME THRILLER: May 30, 2015 – Pittsburgh 6, Harrisburg 5: In one of the greatest wins in the Riverhounds’ history, Kevin Kerr capped off a dramatic finish with a stoppage-time winner at Highmark Stadium. The comeback seemed a long way off as Harrisburg’s Garret Pettis pushed the road team’s lead to 5-3 with only four minutes remaining in regulation. It stayed that way for several more minutes, and then as stoppage time was being announced, the Riverhounds proceeded to pull off their miracle finish.

Danny Earls scored in the early seconds of stoppage time to cut the Hounds’ deficit to one. Then a free kick was laid off to Rob Vincent, who found the upper right corner of the net past Harrisburg goalkeeper Nick Noble. Vincent and his teammates rushed toward the corner flag, thinking that even achieving a draw would have been an impressive feat. But Pittsburgh didn’t stop there as Kerr slotted home the winner, took off his jersey and waved it like a windmill as insanity ensued.

“I really don’t have any words,” Riverhounds Coach Mark Steffens said afterward.

The turn of events said it all.