IOWA CITY -- Iowa has a clear offensive pecking order. Caitlin Clark is the best scorer in women's college basketball history. She has led Iowa in scoring in all but one game this season.

After Clark, Kate Martin and Hannah Stuelke are Iowa's clear #2 and #3 scoring options. Either could be Iowa's second-leading scorer in a given game.

When options 1-3 of the offense average 60 points per game, it's easy to forget about options four and five. That's a mistake. Iowa's fourth and fifth scoring options are key to Iowa's offensive success.

Against Illinois on Sunday, they showed just how vital they can be in Iowa's 101-85 victory over the Illini.

Last year in Iowa's game at Maryland in late February the Terrapins utilized a "junk" defense against Iowa known as a box-and-one. The box-and-one defense has four defenders play in a two-two zone, then has the fifth defender guard the other team's best scorer one-on-one. Against Iowa that meant Clark, and it spelled disaster for Iowa at Maryland. The Terps contained Clark in the game and won 96-68. The Hawkeyes looked like they were in trouble just before March.

They weren't. Other teams tried the box-and-one against Iowa, but guard Gabbie Marshall got hot at the right time. In a rematch against Maryland in the Big Ten Tournament, Marshall went 7-of-13 from three and her 21 points helped Iowa to an 89-84 victory.

Maryland's junk defense keyed on Clark, but that left space open on the wing and Marshall took advantage. Teams tried the box-and-one off and on for the rest of that season, but it was never effective while Marshall was shooting so well.

"It's hard to play box-and-one. It's hard to play zone when we shoot like that," Clark said of Iowa's offense when multiple players are hitting their threes. "It's hard for the other team. Who are you going to take away? Who are you going to sell out on?"

The box-and-one has returned this year. Nebraska utilized it in the fourth quarter of its upset victory over Iowa two weeks ago. Iowa was better against the box-and-one against Michigan in a win 10 days ago, but struggled with the defense again in the loss at Indiana a few days ago.

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Against Nebraska, Marshall shot 0-of-5 from three. Against Indiana, she was just 1-of-2 from deep. Iowa's offensive issues weren't just on Marshall, either. Iowa's options at the two and three positions — Marshall, Molly Davis, Kylie Feuerbach, and Taylor McCabe -- combined for the following stat lines against Nebraska and Indiana:

at Nebraska: 50 minutes, 2 points (1-of-7 shooting), 1 assist, 2 rebounds
at Indiana: 67 minutes, 6 points (2-of-8 shooting), 3 assists, 5 rebounds

Each of those players have had big moments in their careers. Marshall was a star in March last year. Davis had 18 points and 17 points in two games broadcast nationally on Fox against Indiana and Maryland. Feuerbach was a starter as a freshman for Iowa State and had eight points in Iowa's big early season victory over Virginia Tech. McCabe scored 18 points on 6-of-7 shooting from three against Florida Gulf Coast.

The issue has been consistency.

"The one thing coaches cringe about is inconsistency," head coach Lisa Bluder said after the game. "Be consistently good, consistently bad. Be something."

Coming into Sunday's game against Illinois, Marshall had scored seven points or more in just six of the 26 games she has played this season. Davis has been a little more productive, scoring seven or more in ten of 27 games. Feuerbach and McCabe see limited minutes off the bench, but have rarely been able to step up in games where Marshall and Davis aren't hitting.

In a player-to-player (or man-to-man, if you prefer) defense, each defender has at least some help defense responsibility. In a typical zone, defenders guard an area and frequently have to rotate depending on where the ball is.

In both cases, Caitlin Clark has just enough room to work with to find openings to catch, cut, or shoot. In the box-and-one the single "player" defender doesn't play help-side defense. Their sole task is keeping the ball out of their player's hands.

The box-and-one also gives teams double-team opportunities. if Clark dribbles into one of the zone areas, that defender works with the player defender to double Clark.

In those scenarios someone—often a three-point shooter—is open. If Clark finds that open player and they knock down a few open three-pointers, opponents usually abandon the box-and-one. Clark's passing is too good to stay in that defense if Iowa's shooters are hitting shots. If the shooters aren't hitting, then opponents can stay in that defense and Iowa will usually struggle to score.

Shooting issues on the wings also hurt Iowa when teams play traditional defenses. If a player knows their defensive assignment is struggling to shoot, they can play further off that player. That puts them in a better position to double Stuelke in the post or cut off the driving or cutting lanes for Clark and Martin. Hitting shots from three-point range is the answer.

"When we can consistently knock down outside shots, it just opens up the paint for me and Hannah, but really just anybody that wants to drive in there. Cut in there," Clark said.

Marshall, Davis, Feuerbach, McCabe, etc. hitting from behind the arc is vital for Iowa's offense. It gives Iowa's top three options the space they need to work.

On Sunday, Illinois gave Iowa a different defensive look. "They just collapsed on every single drive tonight," Clark said after the game. "It was hard for me to get my feet in the paint and get looks at the rim. They never really adjusted."

The difference was that today, Iowa's fourth and fifth scoring options were on top of their games. Davis scored 12 points in the first half to lead the Hawkeyes and ended the game with 17.

Feuerbach hit two early three-pointerst to help Iowa build its lead and ended the game with nine points total. It was arguably her best performance of the season. McCabe also got in on the action, scoring six points on 2-of-2 shooting from deep. Marshall finished with just two points on 1-of-4 shooting, but her struggles were offset by the strong play from Davis, Feuerbach, and McCabe.

The combined stat line of those four players today:

75 minutes, 32 points (12-of-24, 8-of-16 from 3-point range), 9 assists, 4 rebounds

"We've needed this. We've wanted this to happen," Bluder said of Davis, Feuerbach, and McCabe all playing a big role in Iowa's offense against the Illini.

Bluder is right, too. When Iowa's fourth and fifth options aren't hitting, Iowa's offense bogs down. That bogged-down offense makes the Hawkeyes prone to upsets like the loss against Nebraska and on the road at Indiana. Junk defenses become effective when Iowa's offense gets stuck.

When the fourth and fifth options for the Hawkeyes are hitting shots, though, their offense is almost impossible to guard. Last year, Iowa needed Marshall to step up and be the three-point sniper she was always capable of being. This year, Iowa has more options to fill that role. Davis, Feuerbach, and McCabe can all score from outside just like Marshall did last season.

If one or two of those players can consistently step up each game like they did against Illinois, then Iowa is well positioned for another deep post-season run. The performances of those players -- not the headline-grabbing stats or highlight plays that Clark produces on a nightly basis-- are likely to decide how deep Iowa is able to progress in March this season.