Twice the K-league leaders were trailing but fought back to extend their advantage at the top of the table to 10 points, though second-placed Pohang Steelers are in action on Saturday when they host Gwangju FC.
Jung Sung-hoon was the hero for Jeonbuk, scoring two late goals to give the hosts the points.
Incheon took an early lead through Jung In-hwan but Eninho drew Jeonbuk level after 25 minutes.
Six minutes after the break, Incheon's Brazilian striker Elionar restored the visitors' lead but Kim Dong-chan equalised five minutes later.
Jung Sung-hoon then netted in the 78th and 88th minutes to secure the points.
"We made it hard for ourselves," said Jeonbuk coach Choi kang-hee.
"We need to improve our defending at set pieces and we had problems with our concentration today.
"We now have to focus on the game in Osaka and do our best to get the right result and not make any mistakes away from home."
In the day`s other fixture, FC Seoul crashed to a shock 2-1 defeat at Daegu as their seven-game winning run came to an end.
Kim Hyun-sung struck twice in three minutes just after the half-hour mark to put Daegu in control and while Bang Sung-hwan pulled a goal back early in the second half, the hosts hung on for a famous win.
Seoul travel to Saudi Arabia's Al Ittihad for the first-leg of their Asian Champions League quarter-final next week.