Diego Valeri and Carlos Vela swapped early tallies that stood as the game's only goals until the very last minute, when Mora came through with a flicked-on header that delivered Portland all three points.
The Timbers jumped on top right after kickoff through some vintage magic from Valeri. The Argentine midfielder chested down a long cross from Josecarlos Van Rankin and snuck a clinical finish from a difficult angle underneath LAFC goalkeeper Tomas Romero in just the second minute.
But the visitors would level 15 minutes later through Vela, who found the scoresheet for a second straight game. Diego Rossi laid it on a platter with a perfect cross after running down a longball, giving LAFC's captain a close-range left-footed finish for the equalizer.
The Western Conference sides continued to swap chances throughout the second half, with Valeri coming inches from making it a brace in the 62nd minute after pouncing on an LAFC clearance that didn't make it out of the area. He unleashed a scorching volley, only to see Romero lay out to make the save and preserve the 1-1 deadlock.
LAFC had a few looks of their own, including a near-miss in the 71st minute off a corner kick that was headed on by Jose Cifuentes and tapped home by Rossi right in front of goal. But the Uruguayan forward was whistled for offside and the goal was waved off.
The match seemed destined for what would have been a frustrating home draw for Portland, but Mora ensured that wouldn't be the case. The Chilean forward got his head to a pinpoint cross from Sebastián Blanco and nodded it past Romero at the far post, giving the Timbers the game-winning goal and sending the crowd into a full-on frenzy.
- THE BIG PICTURE: It felt like there was a second-half winner in this one for either team, and the Timbers finally found it, getting the type of result against a Western Conference frontrunner that they'll hope can kick their season into another gear. On the flip side, it's a letdown for Bob Bradley's group, which departs Portland with no points from a game where all three were there for the taking. Still, LAFC have showcased improved form of late, and seeing Vela find the scoresheet again is a net positive.
- MOMENT OF THE MATCH: Felipe Mora's late header was the decisive tally and set off a wild scene at Providence Park.
- MAN OF THE MATCH: Diego Valeri's early opener provided a milestone moment for the club icon, as it marked his 100th career goal for the Timbers across all competitions. Portland's longtime midfield maestro gets the honors for that special occasion, as well as an all-around energetic shift.