Hawkins stole the headlines with a 105-yard kickoff return touchdown for the 49ers, but coach Jim Harbaugh was unhappy with him after he fell foul of the new NFL celebration rules, picking up two unsportsmanlike penalties for pointing the ball at another player as he ran into the end zone and removing his helmet in celebration having scored the touchdown.
The 27-year-old was flagged for a third unsportsmanlike penalty later in the match when he headbutted Vikings linebacker Desmond Bishop, and he admitted that he let his emotions get the better of him at times.
"Those things are not OK to have, especially for the team, I don't care if it's the pre-season. I apologized to the team and I apologized to Coach Harbaugh," Hawkins told reporters after the match.
"I kind of let my emotions get a hold of me. I didn't think, to be honest, I'd be flagged on those. I learned from it."
Hawkins is a new addition to the 49ers' ranks, having been released by the New England Patriots last month.