A six-game undefeated run – coupled with stumbling form from Pohang Steelers – has sent Jeonbuk five points clear at the summit with four rounds remaining before the league splits.
Lee, the division's leading marksman, will now attempt to sink the club he joined Jeonbuk from in 2009.
Seongnam, who have won an unprecedented seven crowns, are in danger of relegation for the first time.
Just one point clear of second-bottom Sangju Sangmu, Seongnam have lost their last two meetings with Jeonbuk without scoring a goal.
Second-placed Pohang Steelers will be expected to keep pressure of Jeonbuk by winning at home to rock-bottom Busan I'Park.
Suwon, level on points with Pohang, make the short journey to bitter enemies Seoul for a fixture known as 'Super Match'.
Seoul and Suwon are undefeated in nine and eight games respectively.
Worrying for Suwon coach Seo Jung-won, who represented both clubs as a player, Seoul have won the last three editions of the derby.
Sangju and Gyeongnam, both in danger of the drop, are away to Incheon United and Jeonnam Dragons respectively.
Finally, Jeju United and Ulsan, with very little to play for in fourth and seventh, square off.
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.