So while Andrighetto was initially offside, a play that was missed by the linesmen, he was able to get onside before carrying the puck back into the attacking end, which soon resulted in a would-have-been goal by Mikko Rantanen.
Based on the rule, the Blues could have only challenged the second zone entry and not the first one that was offside.
On Friday after the team's optional practice at Family Sports Center, Bednar recognized the many issues of the challenge but was also ready to move on from it.
"I think there are two things there. I appreciate them coming out and saying that," said Bednar when asked about the league admitting it had made a mistake. "The original play was clearly offside and probably should have been whistled before the entry we scored on. I think at the end of the day the right [outcome] was made if you use common sense.
"The way the rule sits, the (second) entry was a good entry and the goal could have counted. It was a mistake, and our focus is more on our team game and how we can play and we can't worry about decisions like that. They're doing their best to get the call right on the ice."
Thursday was a learning experience for everyone involved. Not just for the Avalanche, Blues, on-ice officials and the league, but the other 29 NHL clubs as well.
Bednar said his coaching staff looks at every coach's challenge around the league to get a better feel for what is and isn't allowed so they can make an educated decision in the heat of a game.
"We're trying to get real clear on all those calls so we know when to challenge and when not to challenge, and hopefully get it right more times than not," Bednar said. "We learned from last night's call, for sure."
Offside challenges are more high skates this year because of a rule change in the offseason.
In past years, if a team lost its challenge, either for offside or goaltender interference, it would also lose its only timeout. That is still the case this season for interference calls, but lost offside challenges now result in a delay of game penalty for the club that contested the call.