Obliged to travel across Asia to play the final away from home and under pressure throughout the contest, the Qatari side also overcame the heartbreak of conceding a 92nd-minute equaliser which forced extra-time to prevail in a shootout.
Al Sadd goalkeeper Mohamed Saqr, whose was brilliant one minute and woeful the next, saved two penalties in the shootout to allow Nadir Belhadj to score the winning kick and seal the $1.5-million first prize and a place at the FIFA Club World Cup in Japan next month.
"He played fantastic today but believe me, it was not the only game that he was fantastic in this competition," Al Sadd coach Jorge Fossati told reporters of his goalkeeper.
"Today he had a big game, the Jeonbuk players did not miss the penalties, he saved them. It is different."
Al Sadd were under pressure throughout the final at Jeonbuk's World Cup stadium but defended bravely and took two of their few chances to seal victory at the end of a campaign that began in the qualifiers in February.
Belhadj broke down the left and fed Ibrahim Khalfan whose cross was brilliantly controlled by Ivorian Keita who then managed to fire the bouncing ball low into the corner of Kim's goal.
The goal looked set to be the winner as Jeonbuk squandered more chances while Saqr pulled off some excellent saves before making an error in missing a clearance from Eninho's corner to allow Jeonbuk substitute Lee Seung-hyun to head in a 92nd-minute equaliser and take the final into extra-time.
"I really was very worried especially when it went to extra time because, as you can understand, our physical condition to play this game was not the same as normal. When you fly 10 hours two days ago, you need to adapt," Fossati said.
