The sophomore guards scored nearly half of Michigan State's points in over 60 minutes of combined play as MSU (17-3, 7-1) beat the Hawkeyes 71-56.
Lucas tied a career-high with 24 points while turning the ball over only twice in 33 minutes.
Summers, who rocketed into the spotlight last week with a 26-point explosion at Ohio State, scored 21, hitting 2-3 from 3-point land.
The No. 9 ranked Spartans built a 22-point lead before Iowa made things respectable by pulling to within nine with six minutes to play.
State rebounding played a big role in keeping the Hawkeyes down. Senior center Goran Suton pulled down 11 rebounds--five offensive--and snagged two steals.
Freshman Delvon Roe tried to keep up with the primary Spartan big man, logging 10 rebounds in 20 minutes of play.
MSU returns home to the Breslin Center to play Penn State at noon on Sunday, the first of three-straight at home.