The Philadelphia Union are struggling to put the ball in the back of the net, but they're doing a nice job of stopping other teams from scoring.

The Union will try to extend their home unbeaten streak to 10 and take the Eastern Conference lead when they open their season series against Chivas USA on Saturday night.

Since a 6-2 victory at Toronto on May 28 marked the highest-scoring game in its two-year history, Philadelphia (6-4-5) has two goals during an 0-1-3 stretch.

The Union, tied with New York with an East-leading 23 points, were shut out for the second time in five days in a draw against visiting Sporting Kansas City on Wednesday.

"We missed the net a few times and we could have been up by several goals," midfielder Justin Mapp told the Union's official website after the club outshot Sporting KC 7-1. "I think we'll have the same mindset on Saturday against Chivas. Our fans will be behind us. We need to get off to a quick start."

An early goal could be more than enough cushion for the Union, who have yielded three goals in four matches in June and an East-leading 12 overall. Philadelphia, 5-0-4 at PPL Park since a 1-0 loss to Los Angeles on Oct. 7, has posted four clean sheets at home in 2011.

Chivas USA coach Robin Fraser, a two-time MLS defender of the year, knows his club can't miss opportunities Saturday as it tries to avoid losing three straight for the first time since the final three games of 2010.

"We have to be really organized in how we approach them, because they don't open themselves up, they don't give away a lot of chances," Fraser told Chivas' official website. "I think you have to be smart and patient."

Alejandro Moreno could have helped Chivas (4-6-5) pressure Philadelphia, but the former Union forward won't make his return to PPL Park as he is on international duty with Venezuela for the Copa America tournament.

Forward Carlos Ruiz is expected to be in the Union's starting lineup for the second straight match after competing for Guatemala in the Gold Cup, but leading scorer Danny Mwanga (four goals) could be out again with a minor right knee bruise suffered in last Saturday's 1-0 loss at Vancouver.

"It's nothing really big, but the trainer was trying to be safe with it and try not to risk it until I'm back to 100 percent," Mwanga told MLS' official website. "I'm hoping to recover well (Thursday) and Friday and be ready to go Saturday."

Mwanga scored the first goal in this matchup in a 1-all draw on the road July 3. Philadelphia's 3-0 home win over Chivas USA on Sept. 25 was its most lopsided of 2010.