LAKE BUENA VISTA, Fla. — Coach Marc Dos Santos laid out the plan, and his young Whitecaps followed it all the way into the round of 16 at the MLS is Back Tournament.

Substitutes Yordy Reyna and Cristian Dajome scored second-half goals after a lengthy weather delay Thursday as the Whitecaps conjured up an unlikely 2-0 victory over Chicago Fire SC to advance to the knockout stages.

Vancouver needed to win by two goals or more to leapfrog Chicago on goal difference in Group B and move on as one of the four best third-place finishers.

"This is when people are tested. This is when your limits are tested as a human being," said Dos Santos. "This is when you're tired, you can't go any more, you feel everything's against you but you keep pushing.

"That shows a lot of the character that you have as a person. And I think we showed that today ... This was an important step, for sure."

All three Canadian teams will figure in the round of 16.

The Whitecaps will face Sporting Kansas City on Sunday in the knockout round, a matchup decided when the Los Angeles Galaxy tied the Houston Dynamo 1-1 later Thursday.

Montreal plays Orlando on Saturday and Toronto takes on New York City FC on Sunday.

Dos Santos started with a defensive 5-3-2 formation, looking to ensure his team didn't make its task any more difficult by conceded an early goals. The Whitecaps had given up seven goals in losing their first two matches.

"We had to make sure that we stopped that bleeding," said Dos Santos, who threw on more attacking players as the match wore on.

Somehow Vancouver kept the score 0-0 through the first 60 minutes.

Playing their third games in eight days, the Whitecaps had shown little in the first half, outclassed and outshot 10-1 (3-0 in shots on target). Already missing nine players through injury or other reasons, Vancouver lost defender Jasser Khmiri late in the first half with a left knee injury after going down in a tangle with a Fire player near the sideline.

They had a chance to regroup when, in the 63rd minute, the game was halted for 90 minutes as lightning threatened ESPN's Wide World of Sports complex.

A different Whitecaps team came out from the dressing room some 90 minutes later with Dos Santos's substitutions making the difference.

Less than two minutes after play resumed, Reyna broke the deadlock. Ali Adnan found him behind the defence and the Peruvian international sidestepped goalkeeper Kenneth Kronholm before slipping the ball in. It was Vancouver's first shot on target.

Dajome made it 2-0 in the 71st as the Chicago defence was carved open again. Reyna located Dajome, who slotted the ball past Kronholm with his team's second shot on net.

Slovenian international Robert Beric had a gilt-edged chance for Chicago in the 78th minute but skied the ball from right in front on goal.

The Fire briefly had a lifeline in the 84th minute when C.J. Sapong knocked the ball in after Alvaro Medran's shot hammered off the crossbar. But, after video review, the goal was waved off for handball.

Chicago outshot Vancouver 25-4 (5-2 in shots on target), had an 11-0 edge in corners and had 61.3 per cent of the possession.

The Fire had just needed a win to move past Seattle into second place but could still have advanced with a tie or even a one-goal loss in which it scored at least once. Instead they go home early.

San Jose had already clinched top spot in the group.

Dos Santos switched from a 4-4-2 formation to 5-3-2 with five Canadians in his starting 11, including forwards Ryan Raposo and Theo Bair. It marked the first MLS start for Raposo, a 21-year-old rookie from Hamilton.

Third-string goalkeeper Thomas Hasal, a 21-year-old from Saskatoon, also made his first MLS start in place of the injured Maxime Crepeau. Hasal saw his first MLS minutes in relief Sunday when Crepeau broke his thumb in a goalmouth collision in the Caps' 3-0 loss to Seattle.

Backup 'keeper Bryan Meredith left the team earlier in the tournament after the death of his mother.

Crepeau watched the game from the sidelines, his arm in a sling. Jonathan Sirois, a 19-year-old on a one-day loan from the Montreal Impact, was Hasal's backup on Vancouver's nine-man bench.

Dos Santos said it was unlikely the Caps would get Sirois for their next game.

The average age of Vancouver's starting 11 was 23 years four months two weeks with captain Russell Teibert the oldest at 27 years seven months.

Vancouver came to the tournament without forwards Lucas Cavallini, Fredy Montero and Tosaint Ricketts, along with defender Andy Rose and defender/midfielder Georges Mukumbilwa, who all stayed home because of personal or medical reasons.

Defenders Janio Bikel (adductor strain) and Erik Godoy (quadricep strain) were injured in training.

Vancouver lost its tournament opener 4-3 to San Jose. Chicago beat Seattle 2-1 before losing 2-0 to San Jose.

Group games at the tournament count in the regular-season standings, leaving Vancouver at 2-3-0 and Chicago at 1-3-1.