The term "must-win" is used far too often in sports.

But make no mistake about it - Riverside must win its game with Mars to stay in playoff contention.

The two Tri-County North teams will lock horns for a 7:30 p.m. kickoff Friday.

The Panthers (3-4, 2-3) cannot afford a loss to the Planets (3-4, 3-2) after dropping a 21-14 decision last week to Mohawk, the third team from the section vying for the final playoff spot.

"This is absolutely a must-win for us," said Riverside coach Bill Hand. "There's going to be a playoff atmosphere surrounding the game."

Mars is coming off a big 18-7 triumph over Shenango in which the Planets trailed 7-0 at halftime.

"I thought our defense played well all night," said Mars coach Scott Heinauer of a group that forced two turnovers and gave up just 197 total yards. "We didn't give up many big plays.

"But the offense missed some assignments and just didn't play all that well in the first half."

Sophomore quarterback D.J. Cannon, who split time with Josh Keil for three games in the middle of the season, will start under center against Riverside. Keil will begin the game as a wide receiver.

"We're going to go with (Cannon)," said Heinauer. "But it's possible that Josh could see some time at quarterback in certain situations during the game."

Cannon has completed 21-of-46 passes for 364 yards this season. All five of his touchdown passes have come in the last three games.

But the focal point of the Planets' offense will once again be junior fullback Paul Ferrese, who is 36 yards shy of rushing for 1,000 yards this season.

"Mars is a very-well coached team," said Hand. "They run the Wing-T well and are getting better every week. We're going to have our hands full."

Riverside's offense is led by senior quarterback Joe DeSanzo, a Division I recruit who passed for two touchdowns in last week's defeat.

Senior running back John Adams led the Panthers' ground game a week ago with 163 yards while senior wideout Shane Jackson leads the team with 25 receptions.

The last meeting between the two teams was a 41-7 Mars victory in the first round of the 2002 WPIAL Class AA playoffs.