But Emmanuel Osei headed in the tying score just before halftime and Shalrie Joseph, switching to striker in the second half, scored in the 75th minute for a 2-1 Revolution victory. The total-goals series concludes in Bridgeview, Ill., Saturday night.

This was expected to be a tight game, with few scoring opportunities, both teams jockeying for position in preparation for the second game. In five successive playoff series involving the Revolution and Fire, no more than one goal had been scored in the opening match.

But things opened up in the early going and, though both teams struggled with possession, they produced several good chances, each hitting the crossbar or post twice.

“You want to get the first game and put them on their back heel,’’ said Joseph, who scored a career-high eight goals this season. “They’re a great team on the grass and when they play at home. Everybody is a different team when they play at their home stadium. And we’re just going to have to match whatever they bring next week. We know they are going to be fast and playing the ball and ready to go. There’s a lot more on the line, it’s their last game, or our last game if we don’t win. So, you could look forward to a battle, again, you could say.’’

This was certainly an intensely physical matchup. But it was the guile of Cuauhtemoc Blanco that led to the opening score, a 17th-minute goal by Chris Rolfe.

Blanco, with his back to goal, played the ball into space, Marco Pappa running onto it on the right side of the penalty area. With the Revolution’s Jay Heaps and Kenny Mansally converging, Pappa sent a low cross to the top of the goal area. The cross went between three defenders and to goalkeeper Matt Reis, who made a diving stop, but popped the ball directly to Rolfe, who one-timed it under the bar.

Three minutes later, Brian McBride hit the left post.

But the Revolution recovered, capitalizing on Sainey Nyassi’s play on the right wing. In the 25th minute, Jeff Larentowicz hit the left post with the goal open, keeper Jon Busch having failed to clear and colliding with Joseph. Osei advanced and slammed a left-footer just wide in the 40th minute.

Seconds before the halftime whistle, Osei tied it, heading in Mansally’s free kick for the first goal of his MLS career. Nyassi set up the score, winning possession against Mike Banner and C.J. Brown, then drawing a foul from Brown just beyond the penalty area on the left. Mansally’s in-swinger curled to the goal area, Osei losing Banner and flicking the ball past Busch.

The Revolution had success this season moving Joseph to striker in the second half of games. This time, though, it was a move of necessity after Edgaras Jankauskas departed with flu-like symptoms. Joseph produced, roofing a close shot off a scramble following a corner.

“I had a heavy first touch and tried to recover it,’’ Joseph said. “I saw the ball lingering in front of Busch and I just tried to pounce on it and get a toe on it.’’

The sequence was set up as Nyassi won a corner, then Pat Phelan had an open header off Mauricio Castro’s corner kick. Busch stopped that shot, but Phelan slid the rebound to Larentowicz on the right, Joseph then finishing Larentowicz’s low cross from inside the goal area.

Chicago had nearly taken the lead, Baggio Husidic’s 25-yard drive hitting the underside of the bar in the 72d minute. And Nyassi nearly stretched the Revolution advantage, hitting the right post in the 78th minute.

“The object was to win the game,’’ Revolution coach Steve Nicol said. “We would have preferred it went 10-nil, but we know that’s not happening. But we’re ahead, which means they have to come out and come at us. But the object was to be ahead after today and we did that.’’