MANHATTAN — If passing efficiency is your favorite quarterback statistic, you are going to want to watch Kansas State and Vanderbilt go head to head on Saturday.

Jesse Ertz vs. Kyle Shurmur has the makings of an entertaining QB duel.

When it comes to passing efficiency (or quarterback rating, as it's also called) they are two of the best in college football.

Ertz, a K-State senior, ranks fourth nationally with a passing efficiency of 222. Shurmur, a Vanderbilt junior, ranks fifth with a passing efficiency of 217.2. The NCAA passer rating comes from a formula based on passing attempts, completions, yards, touchdowns, and interceptions.

Both QBs are averaging more than 10 yards per attempt, both are completing more than 70 percent of their passes, and neither has thrown an interception.

They are off to incredibly hot starts.

"Ertz has been unbelievable in terms of throwing the football," Vanderbilt coach Derek Mason said. "... He's a much different quarterback than when he first stepped on the scene."

"Shurmur is a young guy that really plays within himself, I think, quite well," K-State coach Bill Snyder said. "He is accurate; he can put the ball where it needs to go. They do not try to reinvent the wheel in regards to what he does. He takes what you give him and he is pretty good about that. That is a real significant trait for a quarterback and that only comes with experience, and he certainly has that."

But here's the thing: Ertz and Shurmur still have a lot to prove.

Though they have torched defenses and appear on their way to breakthrough seasons, their impressive stats have come against soft competition.

Ertz (26 of 37 for 511 yards and four touchdowns) looks more comfortable than ever in the pocket, and he threw for big yardage against Central Arkansas and Charlotte. Can he do the same against a Vanderbilt defense that has forced 17 punts and allowed six points this season?

Shurmur (35 of 46 for 498 yards and seven touchdowns) was nearly flawless against Middle Tennessee State and Alabama A&M. Can he keep that up against a K-State secondary that has already forced six turnovers?

We will find out on Saturday.

This will be the first true test for both teams and their quarterbacks. Motivation is easy to find.

"(Mason) talks about repeatability and having success," Shurmur said earlier this week at a Vanderbilt media session. "We started off 2-0 and now it is time to see if we can continue it. Repeatability is the biggest thing, just trying to go 1-0 this week."

A month ago, few would have thought this game would feature two of the nation's most efficient passers.

But Ertz and Shurmur have made obvious improvements and climbed up the stat charts in similar ways.

Ertz started 13 games for the Wildcats last year and led K-State to a 9-4 record despite injuring his throwing shoulder midway through the season. Now healthy, he is putting his experience to good use.

Previously labeled a run-first quarterback, he is proving he can make big plays with his arm. His average touchdown pass this season is 50.5 yards.

"A lot of people are starting to learn what Jesse can do back there," K-State receiver Dalton Schoen said, "both throwing and running."

Shurmur came to Vanderbilt as a four-star recruit and became the team's starter by the end of his freshman season. As a sophomore, he led the Commodores to six victories and a bowl game, but his production (204 of 375 for 2,409 yards and nine touchdowns) was mediocre.

He now seems to be putting it all together.

"He is a good decision maker," K-State safety Denzel Goolsby said of Shurmur. "He knows where he wants to go with the ball. Trying to get pressure on him is something that we have got to do, get him a little bit out of his comfort zone, because he is a really good player."

K-State and Vanderbilt are off to impressive starts. So are their quarterbacks. Both sides want validation. This is their opportunity to earn it.