Leon Flach (31) celebrates his goal. (Eric Hartline-USA TODAY Sports)

Midfielder Leon Flach scored in the 59th minute to lift the Philadelphia Union to a 1-0 victory over FC Cincinnati in the Eastern Conference semifinals of the MLS Cup Playoffs at Subaru Park in Chester, Pa. on Thursday night.

The Union on Sunday, Oct. 30 will host the winner of the CF Montreal-New York City FC semifinal this Sunday for the right to go to MLS Cup on Nov. 5.

Philly extended their home winning streak to 10 games, tied for the long in a season in club history.

Forward Mikael Uhre sent a short pass across the box to Flach who slotted the ball into the upper left corner of the net. It was Flach’s second MLS goal he had scored in s some 5,400 minutes during the regular season.

“The feeling is a little bit unusual, maybe,” Flach said. “I was not thinking much, which helped a lot. I just tried to hit the ball and saw it flying in the right direction.”

Goalkeeper Andre Blake, named MLS goalkeeper of the year earlier in the week, made five saves to earn a clean sheet and registered multiple saves late in the second half.

“We’re fortunate to have [Blake],” Union head coach Jim Curtin said. “It was a great game from him, he keeps you in it when you need it most. Any playoff run, you need big saves from your goalkeeper.”

It certainly didn’t hurt that the Union had Jakob Glesnes, the MLS defender of the year, on its backline against FC Cincy’s formidable attack.

“I don’t think it’s a coincidence that the best defensive team in the league keeps a clean sheet in the playoffs,” Curtin said. “The lost art of defending, I’m still a believer. That’s what wins championships.”