This post will look at the defensive side of the ball for USC in their loss to Notre Dame. We will first look at the play calling by Notre Dame. Then we will look at the conversion rates allowed by USC’s defense.
Overall, ND ran the ball 31 times (48%) and passed the ball 33 times (52%). First let us look at the play calling by down.
ND stayed fairly balanced on 1st down. However, on 2nd down, ND was nearly 2:1 ratio in favor of running the ball. And finally, 3rd down is nearly 3:1 in favor of passing.
Now let us look at the play calling by quarter.
ND started off passing the ball in the first half holding a nearly 2:1 ratio for passes compared to runs. However, ND started running the ball more in the 2nd half. Their QB’s interceptions probably affected the play calling for ND as the game went on. Also, ND was playing from behind for a good chunk of the 4th quarter. Other than their two runs and a QB kneel to end the game, ND only ran the ball twice in the 4th quarter.
Now let us look at the conversion rates that USC allowed. Overall, USC held strong. Out of ND’s 14 drives, eight of them (57%) did not allow a single first down to Notre Dame. This includes four 3 and outs, three interceptions (two on the third play of the drive and one on the first play of the drive), and a forced fumble (on the third play of the drive). ND averaged only 4.7 offensive plays per drive and 21 yards per drive.
Let us look at the conversion percentages by down allowed.
USC’s defense was able to hold ND to very low conversion percentages on all downs. Unfortunately, there were three long and sustained drives that USC’s defense could not stop. There were two 7-play drives which gained 62 yards and 77 yards respectively. Each ended in a touchdown for ND. There was another drive which had an amazing 16 plays and drove the ball 79 yards on route to a TD. Notre Dame converted seven first downs on that drive, which was nearly half their first downs in the entire game (15 total).
Let us take a quick look at the average distance to go per down compared to the average gain allowed by USC’s defense.
USC was able to stuff many plays quickly. ND was averaging only four yards on 2nd down and 3.6 yards on 3rd down. This is a pretty good sign. One other surprising aspect is the low average yards to go on 4th down. ND averaged 2.7 yards to go on this down. This includes times when ND punted the ball. Generally, teams have a very high average distance to go on 4th down, somewhere around seven or eight yards. This is generally due to drives stalling with incompletions or penalties. ND was able to consistently get close to converting but USC’s defense held them just before the sticks.
Now let us look at the conversion rates allowed by the USC defense on 3rd down by distance.
USC held ND to 2/8 conversions on 3rd and short, which is very good short yardage defense. This is probably the most likely cause for ND’s low average distance to go on 4th down. ND’s only attempt in the 3rd and medium range was successful. On 3rd and long, USC held ND to 1/5 conversions, which is very good as well.
USC’s ability to prevent conversions and generally stop drives helped USC to win the field position battle in the game. ND was starting on their own 25 on average (compared to USC starting on average on their own 46). ND only took 28% of their offensive snaps on USC’s side of the field. Turnovers played a large part of the field position battle as well. Unfortunately, four turnovers which accounted for all of USC’s points was not enough to get USC a win.