Chris Ross has been at the helm of the Medway High boys’ hockey team for five seasons. In his tenure, the Mustangs have not missed the postseason, capturing two sectional titles and appearing in one Division 3 state final.

That impressive run of success starts in goal.

Mike Narducci backstopped the Mustangs to the 2012 Division 3 state final and a subsequent state semifinals appearance.

And for the last three years, Mike Purnell has manned the pipes, while making some history along the way.

Purnell has recorded 21 shutouts in his career, the third-highest total in state history. And with one more, he will move into a tie for second with Needham’s Cap Raeder (1970-72) and Catholic Memorial’s Tom Noble (1992-94).

That stability in goal has helped Medway cement itself as one of the area’s best hockey programs and will make the Mustangs a force to be reckoned with once again with the postseason fast approaching.

When asked which position was most important to his team, Ross wasted little time in delivering his answer, “Obviously goaltender. [Former Boston University coach] Jack Parker said they should rename the game and call it ‘goalie’. I firmly believe that.’’

Ask any hockey coach the most essential player on the ice at any given time and they are likely to have a similar response — and sometimes an identical one.

“Absolutely goalie, no question about that . . . I think Jack Parker once said the sport should be called goalie not hockey because of how important it is,’’ said longtime Waltham coach John Maguire, who has relied heavily on senior net minder Brendan Devlin as his 6-6-2 Hawks inch toward a postseason berth.

“Our program is definitely an example of that, we’ve had some real good goalies over the years that have kept us in games and stolen games. I would put that No. 1.’’

That ability to steal games is what separates the great goalies from the good ones, and what ultimately separates the great teams from the rest of the pack.

Even if a team is struggling in front of him, a goalie — unlike any position in sports — can mask those shortcomings.

“I think especially in high school hockey, the goalie is the one who can change everything,’’ said former Bruins defenseman Hal Gill, a Concord native who played 16 seasons in the NHL and is now in his first season as head coach at Lincoln-Sudbury Regional.

“There’s not too many clean games that you see, there’s going to be mistakes. A good goalie kind of cleans up those and I think the biggest thing is just not giving up those soft ones from the outside.

“If your goalie can limit his number of mistakes and just make the saves he needs to, then that can change your game.’’

L-S has a player with that ability with 6-foot-4 junior Cam Kessler, who can at times be impenetrable thanks to his size and focus on positioning. He has a 1.56 goals against average and .941 save percentage this season.

“He’s been a rock for us back there,’’ said Gill, whose Warriors are 8-4-0. “He’s been really solid, especially when he needs to be, he comes up with two or three big saves a game and that changes everything.’’

Senior forward Eric Holden, who warms up Kessler with shots prior to each game, calls his netminder “very detail-oriented.’’

“Before the games, he’s juggling tennis balls and throwing them off the walls. He’s a very big kid, he takes up a lot of the net, but he also does a good job of coming out when he needs to come out and staying in when he needs to. He cuts down the angles really well.’’

According to Purnell, however, a goalie’s job goes far beyond just flashing the glove or kicking out a pad. Being a voice and another set of eyes in the defensive end can also go a long way in keeping the puck out of the back of the net.

“As a goalie, I look at it almost like a quarterback,’’ said Purnell, who boasts a 1.11 goals against average and a .956 save percentage for the 7-3-2 Mustangs.

“You see everything that happens on the ice. That’s a luxury to me because I can tell all my players what’s happening. If my [defenseman’s] barreling down in the corner and he’s picking that puck up, he doesn’t have eyes in the back of his head. I’m trying to help him and telling him where to cover.

“The goalie, if he helps [the team] get out of the zone that’s less shots for him and less goals.’’

That formula has worked quite well for the senior in what has turned into a historic career. Just this season, he has five shutouts — out of seven Medway wins — and hopes to add to his total over the final few weeks.

But not because he wants to pad his record.

“After my career, I’m going to reflect back on [all the shutouts] and say, ‘Wow that was pretty impressive,’’’ said Purnell.

“But a shutout’s not just the goalie, it’s also a team effort. Everyone’s got to do their job for the goalie to be able to do that. I’ve been fortunate to have good players around me.

“It’s been a really fun ride.’’

Eric Russo can be reached at eric.russo@globe.com.