The Montreal Impact are slumping at the wrong time.

With two games remaining in the regular season and a first-ever MLS playoff berth on the line, the Impact will take a six-game winless streak into Saturday's game against the Philadelphia Union at Saputo Stadium.

The teams are in a three-way tie with the Chicago Fire with 46 points, good for fourth place in the Eastern Conference standings.

"Tomorrow's game against Philadelphia is decisive," Impact president Joey Saputo said Friday. "(The skid) is frustrating as a president and it's frustrating as a fan. But it's not over. With two games left to play this season, we're still at the heart of the playoff race."

Montreal and Chicago are even at 13-12-7, while the Union have one less victory at 12-10-10. The top five teams in each conference will make the playoffs.

Saturday's game will be the third between the Impact and Union this season. Montreal beat Philadelphia 5-3 in May, and the clubs played to a scoreless draw in August.

After sitting atop of the table with the league's best record in mid-June, Montreal is in danger of missing the playoffs altogether. The Impact's latest defeat, a 1-0 loss to the Galaxy in Los Angeles on Wednesday, extended Montreal's scoreless streak to more than 273 minutes.

"For sure there's some nervousness," said Impact sporting director Nick De Santis. "But we're nervous because we were in a positive position, and we've only gotten one point from the last six games."

That point came in a 2-2 draw with Chicago on Sept. 28.

"We've gone through a very difficult time," said De Santis. "We all know what position we're in. We have enough experience, we have enough quality. We've shown that at home we can be a team that's very difficult to play against. Now we need to show up. Tomorrow, it's all on the line."

Some of that experience comes in the form of veteran striker Marco Di Vaio. Despite Montreal's recent slide, the 37-year-old Di Vaio still leads the league with 19 goals.

"We're confident that now's the time to change things," he said. "We don't have much time, we only have two more chances. We know that we can still do something very important for the club and the fans.

"We can't make any mistakes. The playoffs are very important for me."

On Tuesday the Impact announced that Di Vaio, who spent most of his career in Italy, would play another season in Montreal next year. He said the decision was difficult to make because his wife and family are still in Italy.

"I'm very emotional," said Di Vaio. "I want to keep doing what I like to do — play football, score goals.

"When they announced I would stay in Montreal, I received many messages from fans, from everybody. I understood that people liked me here, the way I play. It's more important than anything else."

Saputo wouldn't disclose the details of Di Vaio's new contract. He called Di Vaio the most valuable signing in Impact history.

"It was important to bring a player here who understood our culture and understood what we wanted to do, and who would be here for the right reason," said Saputo. "With Marco 1/8Di Vaio 3/8, we got what we were looking for. It would have been tough shoes to fill if Marco had decided not to come back."