ATLANTA — Coach Paul Johnson hopes Georgia Tech’s defense hasn’t played its best game of the year. It might be hard for the Yellow Jackets to top last week’s upset win over Florida State, a performance that helped snap the team’s longest losing streak in 21 years. Regardless, Johnson is eager to see if the defense can continue to play tough against the run and force turnovers when Georgia Tech (3-5, 1-4 ACC) visits Virginia (2-5, 1-2) on Saturday.