The Portland Thorns walked slowly around the perimeter of Providence Park after the final whistle Sunday afternoon, stopping to high five fans and savoring the unexpected and glorious moment.

It's been a turbulent and trying season for the Thorns, but the defending NWSL champions are headed back to the playoffs.

Thorns forward Alex Morgan scored as Portland beat rivals Seattle Reign 1-0 Sunday afternoon to clinch a berth to the NWSL playoffs on the last day of the regular season in front of crowd of 17,109 at Providence Park.

With the win, the Thorns clinched third place in the NWSL standings and will head on the road to take on second-place FC Kansas City in the semifinal round of the playoffs next Saturday.

"There really wasn't any choice for us," Morgan said. "We couldn't tie. We couldn't lose. It was either we make the playoffs with a win, or we're not making playoffs."

Portland was granted one final opportunity to earn a playoff berth Sunday after the Washington Spirit and Chicago Red Stars failed to earn wins and eliminate the Thorns from contention Saturday.

The results Saturday set up a massive rivalry match between Portland (10-8-6) and first-place Seattle (16-2-6). The Thorns needed a win to advance to the playoffs. With anything less, their season would have been over.

"The only thing that we wanted was to have the chance to come here today with the possibility that if we win, we are in," Thorns midfielder Veronica Boquete said. "And the team did. The feeling right now is amazing."

The Thorns battled back and forth with the Reign in a physical and contentious match as both teams struggled to find the go-ahead goal. Seattle outshot Portland 14 to nine, but it was the Thorns who finally found the back of the net.

"I think from the first minute we played amazing," Thorns goalkeeper Nadine Angerer said. "I think it was our best game in the whole season."

Morgan got her head on the end of a corner kick from Allie Long in the 68th minute and sent the ball inside the near post past Seattle defender Elli Reed to give the Thorns the critical 1-0 lead.

The goal came after a frustrating first half for Morgan. The forward had a great opportunity to score right in front of goal in the 22nd minute, but took an extra touch and was knocked to the ground by Seattle goalkeeper Hope Solo. Morgan appeared to score fifteen minutes later, but the referee called a late foul on Rebecca Moros.

The Thorns' defense, which has been very shaky this season, held strong to protect the 1-0 lead.

Portland defender Nikki Marshall, who was making her 46th consecutive start, was carried off the field on a stretcher in the first half after suffering a knee injury.

Despite losing Marshall, the Thorns managed to keep a Seattle team that had scored an NWSL-leading 50 goals this season off the scoreboard.

"I thought it was a whole defensive performance today," Thorns coach Paul Riley said. "We talked about clean sheets a lot."

Angerer made five saves in the game. In the first half, Angerer managed to tip a point blank shot from Seattle midfielder Nahomi Kawasumi over the net. Then, in the second half, Angerer made a massive diving save to stop a shot from Megan Rapinoe.

"Even until the last second, it was always exciting," Angerer said. "I never felt 100 percent safe because we've given up too many goals this season. I was so concentrated on every single ball. I think the whole defense, the whole team was so concentrated."

The Thorns were coming off a disastrous 2-0 loss to the last-place Boston Breakers last week and were forced to prepare for Seattle knowing that they could be eliminated from playoff contention before stepping on the field.

"We stopped believing that this could be possible," Boquete said. "I think the key was this week, we practiced like there was no tomorrow."

The Thorns can now put the up and down season behind them. They are in the playoffs and anything can happen.

-- Jamie Goldberg | @jamiebgoldberg