"He's finding a way to be effective, not only on the score sheet, but in a number of different areas, decisions on the ice with the puck, his defensive play," Blues coach Davis Payne said. "He's come here to make a statement to our organization after picking him up in a trade this summer and he's doing a very good job of it."
Grachev, a 21-year-old Russian who was acquired from the New York Rangers in exchange for a third-round draft pick, scored at 8:06 of the first period.
The Blues added another goal at 5:02 of the third when Cracknell wristed a shot from the center of the right circle past Varlamov. It was the second goal of the preseason for Cracknell, who also had the tiebreaking score in St. Louis' 4-3 win over Tampa Bay on Wednesday.
The Blues got an empty-netter from Backes with just over 58 seconds remaining on a shot from the blue line following a Colorado turnover by Peter Mueller, who was playing in his first game in a year.
He missed all of last season after suffering a head blow in an exhibition game that brought on another concussion. Mueller also missed the final weeks of the previous season after incurring the initial concussion when he smashed into the boards in a game against San Jose on April 4, 2010.
Avalanche coach Joe Sacco shrugged off Mueller's mistake late in the game, saying he was encouraged by Mueller's overall play and the fact that he was on the ice mixing it up in a game.
"I thought he's coming along," Sacco said. "His game is progressing and heading in the right direction. Once he gets up to speed with his conditioning and his timing, I think he'll be fine."
Sacco added of Mueller, "He's competitive. I want to get him in situations again where he gets used to being out there when there is a minute left and we're down a goal, because he's a guy that's going to be out there when we're in those types of games."
Sacco also said after the game that right wing Brandon Yip suffered a broken forearm when he blocked a shot early in the third period. There was no immediate word on how long Yip would be out.
In addition, the Avalanche said that defenseman Jan Hejda would miss two to four weeks because of a knee injury suffered in an intrasquad game last week.
Paul Stastny scored for the Avalanche from up close 13 seconds later, but it wasn't enough and the Avalanche fell to 0-2 in exhibition play. St. Louis improved to 3-1.
The Avalanche were trailing 2-0 at 12:48 of the third period when rookie Tyson Barie ended Jake Allen's shutout bid with a shot from the top of the left circle that went under the goalie's right leg as he dropped to the ice. Barie also scored a goal in the Avalanche's preseason opener, a 5-2 loss in Dallas on Thursday night.
Allen made 23 saves and Varlamov had 22.
Cody McLeod of the Avalanche and the Blues' Ryan Reaves each served a five-minute major for fighting after dropping their gloves at center ice and pummeling each other with just over 11 seconds remaining in the second period.
Chris Stewart, who starred with Colorado before being sent to St. Louis in a midseason trade last season, did not play.