06/29/2013 09:36 EDT | Updated 08/29/2013 05:12 EDT

Sanvezzo scores sixth goal in four matches as Whitecaps beat United 1-0 for 3rd straight win

WASHINGTON - It took a controversial call for the Vancouver Whitecaps to survive a surprisingly tough road game against the worst team in Major League Soccer.

Camilo Sanvezzo scored his ninth goal of the season on a penalty kick in the second half as the Whitecaps shut out D.C. United 1-0 on Saturday.

In the 48th minute, the Whitecaps (7-5-4) played a long ball deep into United territory, with midfielder Matt Watson sprinting toward it, only to be met hard by D.C. goalkeeper Bill Hamid. Watson crumpled to the turf and referee Matthew Foerster immediately signalled for a penalty kick.

"I'm going to have to watch it again," Watson said. "He definitely got a piece of the ball, but he also went through me. I'm going to have to see it again, to see if it was a PK."

United coach Ben Olsen had no doubt that the call was wrong, not mincing words in his assessment of the officials.

"It's a joke," he said. "We get the same clown show every weekend. Nobody wants to hear the coach in last place complain about the referees. Nobody wants to hear that. But I've got a group of men in there who fought their tails off today, and they're gutted."

Camilo Sanvezzo calmly deposited the ensuing penalty past a diving Hamid into the middle of the net for his third goal in two games and sixth over his last four contests.

On a steamy night during which they were outclassed for much of the first half, the Whitecaps earned just the fifth road win in their three-year franchise history.

"We're on a really good run at the moment," said Vancouver coach Martin Rennie after his team's third straight win. "We have to win on the road more consistently. For us to move up and develop, we need to do that. Tonight, we showed the qualities to do that."

The Whitecaps' defence preserved just their second league shutout of the season in the victory, and their first since a 1-0 home victory against Toronto FC in the season opener on March 2.

Vancouver had not played since June 19, and on a night when fitness was key, the Whitecaps appeared to have the stronger legs in the second half. If not for some spectacular, back-to-back leaping saves by Hamid in the 65th minute, Vancouver would have opened up a wider margin.

D.C. (2-12-3) fired a season-high 22 shots, and had a couple of corner kicks in stoppage time, but could not find the equalizer. After the match, Hamid and John Thorrington berated the officials at midfield.

"I don't get it," Olsen said. "I'm not asking him to be a super referee. I'm asking him to make the right call."

United had the Whitecaps on the defensive for much of the first half, starting in the second minute, when Dwayne De Rosario fired just wide of goalkeeper Brad Knighton. The Vancouver keeper followed with another solid save on Kyle Porter's shot in the seventh minute, as the Whitecaps struggled to control the ball.

Russell Teibert had the best look for Vancouver in the first half, taking a tight-angle shot from the goal-line that deflected off the post behind Hamid in the 11th minute.

The Whitecaps finished June by earning 12 out of 15 potential points, putting them squarely in the hunt in the Western Conference.

"It was a well-deserved win," Rennie said. "On the road, you're not always going to dominate the game, so any way you can get the win is important."

Notes: The Whitecaps' lineup got a lift when both Gershon Koffie and Brad Rusin returned to the pitch for the first time since May 18. Koffie missed five games with a quadriceps injury, while Rusin was dealing with calf problems. … United midfielder Nick DeLeon was not in the lineup, nursing an ankle injury he suffered in the team's Open Cup victory over New England on Wednesday. … The match was a reunion of sorts for United's Alain Rochat, who was traded by the Whitecaps to D.C. on June 6, and Thorrington, who signed with D.C. in the off-season. … Vancouver lost 4-0 in its only other trip to D.C. in August 2011.