Seniors Kelly Robertson and Erin Korp play drastically different roles for the Parkland volleyball team.

Without the two, the Trojans may not be going to a second straight state championship.

Both played key parts in a hard-fought, four-game win over Upper Merion in Tuesday's state semifinals at Council Rock South High School. The Trojans bounced back from dropping the first game 27-25 to win three straight, 25-22, 25-12, 25-21, and set up a championship game rematch with Hempfield at Central York High School on Saturday at 3 p.m.

Robertson, the Trojans' Penn State-bound, all-everything middle hitter, was virtually unstoppable in the match, unofficially recording 40 kills to shatter her previous school record of 27. She was shocked by the final count, as was head coach Mike Krause, and she laughed off the notion of it being the best performance of her high school career.

"Maybe at the net. The net felt really good tonight," Robertson said. "I was a little nervous serving and playing defense, but fortunately we have outstanding defenders. Callie [Krajcir] and Abby [Hawk] and Morgan [Rentzheimer] all did really, really well passing. I couldn't do anything at the net without them or Taylor [Krause] putting the ball up for me.

"I've never been a mental tracker of that. It's always been about the next one. I don't care how many I've had before, it's just about that kill. I don't think about the records or the books or anything."

The only spot where Robertson seemed vulnerable was on the back line, where she committed four service errors. But Korp, a senior co-captain used sparingly, came on in relief to provide a spark from the service line when the Trojans needed it most.

With a raucous Viking crowd raining chants of "Overrated" onto the state's top-ranked squad and Upper Merion's unorthodox style seeming to be the kryptonite for Parkland's attack, Korp stepped to the line. The match was tied at one game apiece and the Trojans held a slim 6-4 lead in the third game. Korp reeled off five straight points to give the Trojans their biggest cushion of the night to that point. In that span, she game up with a pair of passes off digs that led to kills from Allora Atiyeh and Alicia Weigel. She later finished off the third game with an ace.

"She was great. She really brought some energy to us," Krause said. "With the length of our matches, we've been limited in our subs. And fortunately in that third set, we were able to use them and it worked out great."

The Trojans were coming off a five-set thriller on Saturday over one of two other teams to be ranked number one in the state this year, District 1 champ Bishop Shanahan. On the long bus ride to Council Rock South, Krause didn't quite sense the same urgency that his team had for that match, but knew Upper Merion would present problems with their style of play, which included wider outside hitters taking untraditional attacking angles.

After dropping the first set, assistant coach Debbie Tice did her best to ignite the team.

"Debbie talked to them and told them it was about confidence," Krause said. "We had to play and control what we could do. We were almost overanalyzing and trying to adjust too much to what they did. We had one day to prepare and that's the type of team you have to really go through what they're going to do."

The Trojans are much more familiar with Hempfield, which began the year ranked number one and held that spot for two weeks before ceding to Bishop Shanahan. The Black Knights are making their third straight trip to the PIAA championship game, winning the 2010 title over Upper Merion and falling to Parkland last season. Hempfield took the first meeting between the teams, 25-21, in a one-game showdown at the Garden Spot Invitational on September 8. The Trojans got revenge in the rematch, winning 25-16, 25-19 in the finals of the State College Invitational on September 29.

"We've played them in tournament and we've lost to them and we've beaten them," Robertson said. "But that doesn't have anything to do with what's coming up now. Every team gets better, no doubt.

"[Getting back to the final] was always wishful thinking at the beginning of the year. It was definitely a possibility, but the fact that everybody kept saying, 'You've lost six starters. You've lost so much.' It kind of tore you down mentally. You started to think it yourself. But the more we played, the more we started to think, 'Ok, we can do this.' It's worked so far."