ANAHEIM -- The man with the perpetual scowl and the personality drawn from cactus and shards of glass seems to have been built for this game.

Ryan Kesler was not just built for a Game 7 with a trip to the Stanley Cup finals hanging in the balance, but the Anaheim Ducks believe he was built specifically to help carry them through a game like Saturday's Western Conference finals finale.

No team -- especially teams like the Ducks and Chicago Blackhawks, who have delivered six classic punch-counterpunch games -- will advance to the Stanley Cup finals because of one player.

The game is too fast, too complex; the lines separating success and failure too fine for it to be that simple.

But these games are the domain of the stars, the leaders, the players who do not shrink from challenge but grow large in the face of it.

A player like Ryan Kesler, perhaps?

"He is a force to be reckoned with when he's on his game," one team executive familiar with Kesler's evolution said.

Doesn't matter if Kesler doesn't have the sunniest of dispositions, "when the chips are down, he's a performer," the executive told ESPN.com.

"These are defining moments for guys like him. This is a real opportunity for him. It's the type of game where he could have a huge impact."

Kesler has always been a little polarizing. Certainly opponents have long felt great enmity for the big center.

But even in the locker room with the Vancouver Canucks -- where he started his NHL career after being selected 23rd overall in the marvelous 2003 draft -- he was not universally loved. Nonetheless, he grew into one of the fiercest competitors in the NHL, winning a Frank J. Selke Trophy in 2011 as the game's best two-way player.

Injuries connected to his hard-edged style of play limited his effectiveness at times, but Kesler helped create a perpetual contender in Vancouver, until he decided last summer he needed a change and the Canucks acquiesced.

On the shortest-of-short list of teams Kesler would agree to be traded to was Anaheim.

"I know this team can win," Kesler said Friday. "When you get a taste of the Stanley Cup finals and you get that close, you want to be back. I think we all know, careers don't last forever. You only get a kick at the can a couple of times. That's why."

The Ducks gave up defenseman Luca Sbisa, forward Nick Bonino and a first- and third-round draft pick for Kesler (and a third-round pick), hoping his presence down the middle would be the final piece to a championship puzzle.

More than simply providing a top-level center to complement captain Ryan Getzlaf, the Ducks were hoping Kesler would also add that final piece to the mental makeup of a team that had lost in the playoffs in Game 7s at home the past two seasons to the Los Angeles Kings and Detroit Red Wings.

"Kes, I'd love to say a bunch of stuff surprised me, but my opinion of him is kind of the same as it was," Getzlaf said Friday.

"He's a great player. He plays hard. He makes it hard on you to play. I've been in [Jonathan] Toews' shoes many times, many games, and it's not easy. Kes does a great job and he has the offensive threat that makes him even more reliable for us when he can play at both ends of the rink."

It's not surprising Kesler has been engaged in a nightly battle of wills with Chicago captain Toews throughout this series. Those are the matchups Kesler has embraced for years, especially when he was with Vancouver and the Canucks and Blackhawks clashed in three straight postseasons from 2009 to 2011. They will go at it with the season on the line in Game 7 Saturday night (8 ET) in Anaheim.

That battle will significantly effect Saturday's outcome, one way or the other.

"A challenge. He wins some nights, I win some nights," Kesler said. "That's the way it goes when you have that caliber of player you're trying to defend.

"It's been no different than other series, obviously a battle, but it's just a piece of the pie. One battle of many."

Toews agreed Kesler has added some grit to the Ducks.

"I guess back in his Vancouver days with that team there was a lot of rivalry there. He's one of those guys I think added to the Vancouver Canucks' reputation that we didn't like them too much and they didn't like us. I'm sure he's bringing a little bit of that edge to Anaheim," Toews said earlier in the series. "He's been a good player for them. Offensively, he's someone we have to look out for as well. We know he plays a real solid two-way game. He'll be the type of guy that will be playing physical and trying to take some of our top players off their game as well."

What has always impressed longtime NHL and international coach Ron Wilson about Kesler is his ability to agitate as well as turn in dominating offensive performances, a rare blend.

"He is an impact player. What I remember most about him, he has a way of getting under the player he's playing against's skin," said Wilson, who guided Kesler and the Americans to a silver medal in the 2010 Vancouver Olympics.

"Even if he just looks at you he's irritating you. It's magical. He takes great pride in it, too," Wilson told ESPN.com prior to Game 7.

Part of the Kesler package, though, is that as prickly as he plays, there is some of the prickle that is part of his personality away from the rink, too.

"He never looks happy, he constantly looks pissed off," Wilson said.

He recalled repeatedly asking Kesler if everything was OK. To which Kesler would react with puzzlement, "Yeah, everything's fine, why do you keep asking?"

"He's not a naturally friendly guy, I'll say that," Wilson said. "He's always got something rough around the edges that you're never going to smooth over. That's what a coach loves about Ryan.

"He plays pissed off. There's nothing phony about Ryan."

Another source familiar with Kesler's evolution said an organization has to balance how that personality might effect the locker room with how integral that personality is to his significant presence on the ice.

"Quite simply, he's a horse. He's a guy you can ride," a team executive said.

Game 7s, especially at this stage of the playoffs, are defining moments.

If the Ducks lose and Kesler does not play well, does that diminish his reputation?

Maybe. But Wilson thinks that would be unfair.

"Defining moment? I think that's too much," Wilson said. "Ryan doesn't look at the game in that light. He realizes he's just one player. And the guy he's shutting down is just one player, although it might be the most important player in the league in Jonathan Toews.

"He's been in plenty of big situations and with big responsibilities. I'm not really looking at this as Ryan Kesler's defining moment, to be honest with you. Is it a big moment? Yes, it certainly is."

Defining or not, this is certainly a moment that provides a tremendous opportunity for Kesler and the Ducks.

Whether it's shutting down Chicago's power play as a key penalty killer or limiting Toews, who is likely to play alongside Patrick Kane again, or scoring a power-play goal, Kesler has a world of opportunity at his fingertips Saturday.

Ducks coach Bruce Boudreau wouldn't speak to Kesler's personality, but said, "Ryan Kesler plays angry. He looks like he's a man possessed when he's out there, as does Toews. That's why those two have such great battles. But [Kesler] sure brings a great determination and will, and that's all you ask for. I'm not trying to get into our heads anymore. It's Game 7, boys, lay it on the line."

The trade that brought Kesler to Anaheim seems like a long time ago. But that moment looms large with Saturday's game in the offing. So much on the line for both the player who found himself drawn to this franchise and the team that strongly believed he was a cornerstone piece to a Stanley Cup puzzle.

"Until you've won it, you're not a champion," the team executive said. "He has an opportunity to be a significant piece of a championship team."

To be that piece, to find that elusive championship ring, both Kesler and the Ducks must first face this one singular challenge on Saturday night.