03/08/2014 10:43 EST | Updated 05/08/2014 05:59 EDT

Mauro Diaz helps FC Dallas beat Montreal 3-2 in coach Oscar Pareja's debut with team

FRISCO, Texas - Even without its offensive centrepiece, the Montreal Impact's offence seemed quite healthy in its MLS season opener.

The defence, however, was another matter.

Though they generating scoring chances in bunches — even with 2013 leading scorer Marco Di Vaio watching from a box — the Impact couldn't overcome its shaky defence in a 3-2 loss to FC Dallas on Saturday night at Toyota Stadium.

"We gave up three goals. It's hard to win when you give up three goals," coach Frank Klopas said. "There were situations we could have avoided and handled better.

"We had the shots on goal, we pushed the game, we created chances … but we've got to limit the goals or it's going to be difficult. We scored two goals on the road and had more chances, so you figure you've got to walk away at least with points."

Instead, Montreal has none, as Dallas' speedy attackers consistently drove the ball deep and put the Impact's defenders in difficult positions. On two occasions those turned into fouls that led to FCD goals.

Dallas' Mauro Diaz blew past midfielder Sanna Nyassi on the right wing and cut inside toward the goal in the 23rd minute of a 1-1 game. Defender Jeb Brovsky caught him from behind, but Diaz went down on minimal contact in the box, giving Dallas a penalty kick that Blas Perez converted.

"I felt like I could have sneezed harder and the guy would have fallen over," Brovsky said. "But that's part of the game. … The play should have stopped before that, and I had something to do with that. I'm not happy about that, but you move on."

Diaz scored on a curling 20-yard free kick in the opening minutes of the second half to give Dallas a 3-1 lead after Montreal's Hernan Bernardello was called for a handball as FCD again threatened.

The Impact made Dallas sweat despite the chilly conditions — 5C with 24-kilometre per hour winds at kickoff — by continuing to press the attack.

It paid off in the 65th minute when Andrew Wenger, taking the lead forward role usually manned by Di Vaio, headed a pretty cross from Felipe past Dallas goalkeeper Chris Seitz to close the gap to a goal. But Seitz came up big in the final minutes to close the door for FCD.

Di Vaio's absence — the result of a three-game suspension earned in an ugly shoving match during last season's playoff loss to Houston — didn't keep the Impact from putting together a dangerous attack. Montreal got off 15 shots, nine on goal and many at point-blank range, and put two of them in the net, both on textbook plays.

"We probably could have had another two goals if we had just been sharper," Wenger said. "Marco's a fantastic player and a large part of our offence, but a lot of guys stepped up tonight and helped create opportunities. If we continue that the entire season, we'll be lethal."

Montreal had a huge early chance when rookie Eric Miller, in his MLS debut fired toward a seemingly open net off a third-minute corner kick. FC Dallas defender Jair Benitez slipped into the goal and blocked the ball off the line, then helped Seitz stop Hassoun Camara's follow shot on the rebound.

But seven minutes later, the Impact broke through for as 1-0 lead, as midfielder Justin Mapp weaved through three defender before threading a perfect cross to the foot of Nyassi, who tapped it into the corner of the net.

It took Dallas only two minutes to tie it, with Fabian Castillo collecting a deflected ball in close and drilling it past keeper Troy Perkins.

"It was a little bit of frustration, but you have to grow from that," Camara said. "When you allow three goals, you're never happy. We have to be more intelligent.

"But at the same time, it's very easy to correct that. We can do much better."