I assumed taking a game lightly was a pretty common knowledge term around sports fans. For example, my local OHL team had two games this weekend - the first, against a team 10 points back of a playoff spot, and the next day against the #2 ranked team in the country who they had lost 3 previous very close games to. The coach spoke before the game of making sure the team was up for the first game and not looking past it in anticipation of the 2nd game, likely to be a much more passionate game.
As it turned out, that 1st game had no energy, was sloppy and they barely scraped out a win.