(Photo credit: Troy Wayrynen-Imagn Images)

Gage Guerra scored a dramatic stoppage-time leveler to help the Portland Timbers prolong their MLS Cup Playoff campaign, with the hosts prevailing 3-2 on penalties following a 2-2 draw with San Diego FC on Saturday night.

Guerra's goal -- on a header of Ariel Lassiter's cross -- was his first in nine appearances across all competitions for the Timbers after spending most of the season with the club's MLS Next Pro side.

Western Conference top seed San Diego then missed the target on its last three penalties, allowing the eighth-seeded Timbers to prolong the best-of-three Round 1 series and force Game 3 next week in Southern California.

Halftime substitute Chucky Lozano put San Diego in front in the 51st minute after off-the-field drama led to him being a healthy scratch for his side's playoff opener.

Kristoffer Velde scored his second goal of the season early for Portland before Amahl Pellegrino pulled San Diego level deep in first-half stoppage time. In between, San Diego goalkeeper CJ dos Santos was forced out of the match following a scary collision with Luca Bombino, his own defender.

But Velde was among those Timbers players who looked like they would be punished for wasteful finishing in their bid to find a leveler. The summer signing forced Pablo Sisniega -- dos Santos' backup -- into a save from about 10 yards out in the 71st minute, then sent a header from a promising position wide of the post in the 74th.

Then, in the 88th minute, Felipe Mora, who scored in Portland's West wild-card victory over Salt Lake, also missed the target with his head from an even better position.

However, Guerra would keep his nerve when he reached Lassiter's cross from the left near the byline, powering a header from about eight yards between Sisniega and the right post.

Lozano was San Diego's first-ever designated player, signing as the expansion team joined MLS this season. His omission by manager Mikey Varas for Game 1 followed a reported verbal dressing room altercation earlier in October.

The Mexican star apologized on social media, and Varas indicated earlier this week that Lozano would likely be available for Saturday's Game 2.

He entered at halftime for Corey Baird and put San Diego in front six minutes later.

It was an attack down the left, with Anders Dreyer's volley of Franco Negri's chipped cross forcing James Pantemis into a sprawling stop. Lozano was first to the rebound to finish off his first goal since Aug. 31.

--Field Level Media