The Blues, who were last in the NHL standings on Jan. 3, played Game 1 of the Western Conference Final at the San Jose Sharks on Saturday.
"When we asked Craig to take over the team (in November), we were in flux at that point," Armstrong said. "I said to Craig: 'You take over on the interim basis and we'll go from there.'
"We were going to support Craig and we were looking outside at potential candidates, whether it be major junior, Europe, the NHL, the American Hockey League. And as I started to work with Craig, whatever names were on the (candidate) list started to get crossed off and crossed off.
"Then I found the synergy that Craig and I have had. Now we're at a list of one."
The Blues were 7-9-3 when Berube replaced Mike Yeo on Nov. 20. By Dec. 31, they were 15-18-4. St. Louis closed the season 30-10-5 to finish third in the Central Division (45-28-9).
They defeated the Winnipeg Jets in six games in the Western Conference First Round, then eliminated the Dallas Stars in a seven-game, second-round series.
Armstrong said he and Berube, 53, will negotiate a contract in the offseason. The focus now for the Blues is defeating the Sharks and trying to win the Stanley Cup for the first time.
"San Jose**
