The Monarchs take a 2-0 lead in the best-of-seven with them to Wilkes-Barre, where Game 3 is scheduled for Saturday night.
Weal (2g, 1a), O’Neill (2g, 1a) and Michael Mersch (3a) each had three points on the night for Manchester, and the trio has now combined for 32 points through seven playoff games.
Manchester got on the board first 9:28 into the game as O’Neill carried the puck out of the left-wing corner, skated in front and wired a shot into the top corner over the glove hand of Matt Murray.
The 1-0 lead stood up until the teams combined for three goals in 24 seconds during the second period.
First, Penguins rookie Conor Sheary slipped a shot just across the goal line on a power play at 12:28, tying the score at 1-1.
But just 10 seconds later, Justin Auger picked up a carom off the right-wing wall, went backhand-to-forehand and tucked the puck around a sprawling Murray in for his first goal of the playoffs and a 2-1 Monarchs lead.
Manchester grabbed the lead back for good with 2:57 left in the middle frame as O’Neill moved the puck from the goal line back to the right point, circled and sent a pass cross-ice to Weal, who snapped a shot home from the bottom of the left circle to put the Monarchs up 3-2.
Weal then gave Manchester its first two-goal lead of the series with his second goal of the game and seventh of the playoffs, a power-play marker at 5:24 of the third to make it 4-2. It was the first power-play goal allowed by the Penguins in five games this postseason.
O’Neill picked up his second of the night into an empty net with 2:03 remaining to complete the scoring in Game 2.
Jean-Francois Berube (5-2) made 18 saves for his 11th consecutive win on home ice, as the Monarchs held their opponent to 20 shots or fewer for the fourth time this postseason. Murray (3-2) stopped 29 of 33 shots in the loss.
Eastern Conference Semifinals – Series “I” (best-of-7)
1-Manchester Monarchs vs. 4-Wilkes-Barre/Scranton Penguins
Game 1 – Wed., May 6 – MANCHESTER 4, W-B/Scranton 3 (3OT)
Game 2 – Thu., May 7 – MANCHESTER 5, W-B/Scranton 2
Game 3 – Sat., May 9 – Manchester at W-B/Scranton, 7:05
Game 4 – Mon., May 11 – Manchester at W-B/Scranton, 7:05
*Game 5 – Tue., May 12 – Manchester at W-B/Scranton, 7:05
*Game 6 – Fri., May 15 – W-B/Scranton at Manchester, 7:00
*Game 7 – Sat., May 16 – W-B/Scranton at Manchester, 7:00
*if necessary… All times Eastern