Sevilla opened the scoring in the 7th minute when Luuk de Jong fired home with his left foot after Barca failed to deal with a corner, but Barca levelled barely a minute later when Jesus Navas was unable to clear Jordi Alba's ball into the area, allowing Coutinho to pick his spot.
Moments later, new arrival Joel Pohjanpalo scored his first goal for Union only 35 seconds after coming on to put the result beyond doubt in the 64th minute.
The Iranian giant advanced to the ACL final with a 5-3 win on penalties against Al Nassr after the West Zone semifinal ended 1-1 in 120 minutes at the Jassim bin Hamad Stadium on Saturday.
5. Colombia: The old and the new
Other leading clubs in Europe announced similar figures. Manchester United shipwrecked with an 80 million offer for Jadon Sancho as Borussia Dortmund demanded 120.
A win for Barca would carry the positive feeling into the international break, but Sevilla will also look at this game as the chance to show they are title outsiders this season. Enditem
With Sichuan's offense bogged down, Dongguan retook the lead and delivered the final blow with efficient offensive late in the fourth to make it 78-71.
Barca issued a communique shortly after the final whistle confirming Alba had "problems in his right hamstring," adding that he would undergo tests on Monday to discover the full extent of the injury.
The 28-man squad is headed by Barcelona forward Lionel Messi and also includes Juventus attacker Paulo Dybala and Inter Milan striker Lautaro Martinez.
Earlier on Friday, Jiangsu defeated Shanghai 3-0 (25-17, 25-20, 26-24) in the third-place match.
"This might be another painful setback, but after all, it delivered valuable hints of the topics we have to work on," Baum said.