Tim Parker remembers feeling pretty good after the Vancouver Whitecaps secured a scoreless road draw with the Portland Timbers in the first game of their Western Conference semifinal in 2015.

Sure, they wasted a couple of chances that would have provided a significant edge in the aggregate series, but with the Whitecaps hosting the second leg, Parker was confident.

"We thought we were going to be able to come back and take care of business," the defender recalled. "Unfortunately that wasn't the case."

The Timbers scored a priceless away goal in the first half at B.C. Place Stadium, meaning the Whitecaps all of a sudden needed to find the back of the net twice to advance. It was a gut punch Vancouver never recovered from in what eventually turned into a season-ending 2-0 loss.

While that result still stings two years later, the Whitecaps are hoping the script reads the same way in 2017 — only this time in their favour — when they visit the Seattle Sounders in Thursday's second leg of the conference semi following Sunday's uneventful 0-0 tie in Vancouver.

"We have to look forward to being the underdog down there in Seattle and hopefully ruining the story for them," said Parker.

The Whitecaps and Sounders played things extremely tight to the vest in Sunday's first leg — a game that saw just one shot on target and very little in the way of creativity going forward as both teams looked to avoid the big mistake.

While the conservative setup of Vancouver head coach Carl Robinson was a surprise to some, the Welshman said afterwards he learned the hard way against the Timbers that conceding even one away goal in two-legged ties can be a death sentence.

"I was feeling very confident after going to Portland away from home," said Robinson, who was in his second year in charge in 2015. "When they scored, I still remember shaking my head thinking, 'Right, that away game is gone now. We need to score two goals.'"

As it stands, a Vancouver win or a draw with scoring would be enough for the Whitecaps to advance to Major League Soccer's West final against either Portland or the Houston Dynamo on the away goals rule.

A Sounders' victory by any margin would see them move on, while another 0-0 result means extra time and the possibility of a penalty shootout.

"It's not how it started, it's how it ends," said Vancouver striker Fredy Montero, who played for Seattle from 2009 to 2012. "We have a big chance here."

Part of the reason for the Whitecaps' muted approach in the first leg also came down to the absences of offensive catalysts Yordy Reyna and Cristian Techera from the starting lineup because of injury. The dynamic midfielders eventually subbed on in the second half, but are both in a race to be fit for Thursday.

On the other side, the defending-champion Sounders will have striker Clint Dempsey back from suspension at what will no doubt be a raucous CenturyLink Field after he was sent off in their regular-season finale.

Robinson chose his words carefully when asked about the U.S. international, who could have been banned another game or two for the elbow that resulted in the red card, or his sarcastic applause directed at the referee before slowly leaving the pitch.

"Listen, I'm not here to talk about them," said the coach. "People have their jobs to do, rightly or wrongly. Obviously Clint's a good player. Whether he got what he deserved ... it's down to them guys."

The Whitecaps are also expecting to see Sounders midfielder and captain Osvaldo Alonso (quad strain) from the start after he joined the fray as a sub in Sunday's second half.

"Those are the guys that are going to hurt us," said Parker. "It's important to keep tabs on them."

The Whitecaps, who lost 3-0 in Seattle on Sept. 27, finished third in the West before trouncing the San Jose Earthquakes 5-0 in the single-elimination knockout round for the club's first-ever playoff victory last Wednesday. Seattle had a week off between the end of the regular season and first leg in Vancouver after grabbing second and a bye to the semis.

The Sounders owned the West's second-best home mark at 11-1-5, while the Whitecaps had the conference's top road record at 6-9-2 thanks in large part to a style that relies heavily set pieces and counter-attacks for offence.

"It's all set up nicely," said Robinson. "We'll give it our very best.

"Hopefully someone will step up and become a hero."

Something the Whitecaps didn't have at this stage two years ago.