Celtics prepare for Game 5 against the 76ers

BOSTON (WHDH) -- The Celtics are coming off a Game 4 loss where the C's blew a double digit lead in the second half. Monday night’s Game 5 promises to be the Celtics’ biggest game to date this post season.

If they win, the Celtics will have a considerable edge over the 76ers. If they lose, they’ll find themselves in a similar situation after blowing an 18-point lead in Philly in Game 4.

"We had to close them out. You know, we had to continue to pound, and I just thought we lost our aggressive nature," said Ray Allen.

A lack of aggression, A lack of composure, and now, a lack of security -- the Celtics are on high alert now that the series with the 76ers boils down to a best of three.

"You just feel like there's a sense of urgency. You feel like once you lose that game, you don't want to come back -- you really want to come back and play the next day. You know, that's the way I felt," Celtics Captain Paul Pierce said.

"You know, I keep saying with our team, we don't do it the easy way, but I don't think we could," said Doc Rivers, Celtics head coach.

They blew an 18-point cushion in Game 4, and a chance to take a 3-1 lead on Philly. But Doc Rivers knows what gives his team an edge when the going gets tough.

"I just think they're mentally tough, and that's what they've been all year," Rivers said.

"A lot of it is mental - you know, preparation, mental, understanding what it takes, you know, all those things, a combination of those things really help us out, being a veteran ballclub," Pierce said.

The 76ers don't have the same wealth of experience, but right now -- their confidence is carrying the load.

"That’s our mindset that we want to go and win. We're not just happy, we're not just satisfied saying, 'Hey, we made the second round, gave them a good fight,’ you know, guys are really focused in, and guys are excited about this opportunity, and we're looking forward to making the most of it," said Andre Iguodala, 76ers forward.

The 76ers, an 8-seed, have nothing to lose. Their post-season is already a success having knocked of the top-seeded Bulls. And as the Celtics learned in Game 4, it makes the 76ers a very dangerous team.