TORONTO — Newly acquired forward Andrew Wiedeman scored his first MLS goal to lift Toronto FC to a 2-1 victory over the slumping Rapids on Wednesday night.

Fullback Doneil Henry started the play on the go-ahead goal in the 68th minute. Beating a defender in the corner, he sent the ball toward the box and, after rookie Luis Silva swept it toward goal, Wiedeman poked it in.

Colorado dropped its fourth in a row. It also marked the fourth time this season it has lost after opening the scoring, second only to Montreal (five).

“Sometimes in games like these you are searching for answers.” Rapids coach Oscar Pareja said. “And today’s game is one of those games where we lost more than the points. I felt we lost our identity, and that is very disappointing.”

The 22-year-old Wiedeman was playing in just his 10th career MLS game and was making his second appearance as a substitute since coming to Toronto last Friday in the deal that sent Julian de Guzman to FC Dallas.

Conor Casey scored in the 23rd minute for Colorado (7-12-1). Jamaican international Ryan Johnson, making up for a flubbed penalty in the third minute, replied for Toronto (5-11-4) in the 51st.

Coming in on the back of victories over New England and Vancouver, Toronto FC is now riding its first three-game win streak since 2008 — its second season.

The Rapids have lost all six games against Toronto at BMO Field, although it defeated FC Dallas in Toronto to win the 2010 MLS Cup.

“We’re definitely sliding,” Casey said. “We just haven’t been able to find a way to win.

“It is kind of hard and frustrating right now to be able to really analyze the game. We’re losing ground and we have to do something to change things around because we’re not doing well and we’re not getting points.”

The Toronto win, in front of 18,225, continued TFC’s revival under head coach Paul Mariner. Toronto is 4-2-4 under Mariner — after a 1-9 start under former manager Aron Winter — despite playing those 10 games in 32 days, with six on the road.

Wednesday’s game was the seventh for Colorado (1-6, with all of the losses by one goal) over the same time period.

The contest was the first for Toronto since leading scorer Danny Koevermans tore knee ligaments in Saturday’s 1-0 win in New England. The designated player is not expected to be back until next May.

Johnson hit the outside of the post on a third-minute penalty after Silva was clumsily hauled down as he collected a through ball and danced past goalie Matt Pickens with former TFC defender Marvel Wynne trying to catch up on the play.

Johnson was also wide on a header in the sixth minute.

It was a nightmare start for Colorado, which was repeatedly carved open at the back, but Toronto could not take advantage.

The Rapids had their first chance in the 18th minute when Brian Mullan hammered a long-range right-footed rocket off the post.

Five minutes later, Casey put the visitors ahead after a nice give-and-go off a Rapids throw-in. It was the 50th MLS career goal for Casey, who appeared in two games for Toronto in 2007 before moving to Colorado.

“First and foremost, we need to rest up and get our legs back and make sure we are physically ready to go,” Casey said of the Rapids. “That is where the main focus is now and we will think about the rest of it once game day comes.”

Colorado wore black armbands to honor Marisa Colaiano, its senior manager of community relations. She died Tuesday as a result of complications from multiple sclerosis. The Rapids will also wear them against Real Salt Lake on July 21.