The best hockey is during the playoffs because all the players are giving their 110% if they want to win.

Anthony Dionne is no stranger to this and we all saw it in the S75 playoffs. He was completely dominating all the other goalies before the conference final. 
Texas had the best defense in the league and Dionne was a big part of it. Only 12 goals allowed in 9 games during the first two rounds. Texas was the favorite and Dionne was not allowed to loose and he really stepped up in those games.

In that time of the year, your goalie need to be one of your best player if you want to have a chance at the Cup. They play all the games of their teams so they have to be mentally and also physically strong for the long run.
Dionne played 54 games this season and he's still clearly the number one goalie for Texas and don't expect him to miss a game.