The U.S. Open Cup final four will be determined tonight, with four quarterfinal games taking place across the country.

In Philadelphia, the Union will look to continue building momentum under interim manager John Hackworth against affiliate and upstart USL Pro club Harrisburg City Islanders. At Livestrong Sporting Park, Sporting Kansas City will aim to put the disappointment of Saturday's loss to the Union in the rear-view mirror against the Dayton Dutch Lions, who just won their first USL Pro game of the season.

On the West Coast, Seattle's quest for a fourth straight Open Cup title faces its biggest threat as the Sounders face a red-hot San Jose Earthquakes side. Down the coast, Chivas USA will look to fend off USL Pro's Charlotte Eagles, who have already beaten FC Dallas en route to the quarterfinals.

Here is the viewing schedule and links to free streams for tonight's action:

7:30 p.m. – Philadelphia Union stream – Philadelphia Union vs. Harrisburg City Islanders

8:30 p.m. – Sporting Kansas City stream – Sporting Kansas City vs. Dayton Dutch Lions

10:30 p.m. – Chivas USA stream – Chivas USA vs. Charlotte Eagles

10:30 p.m. – San Jose Earthquakes stream – San Jose Earthquakes vs. Seattle Sounders

SBI will be providing live commentary for tonight's matches, so please feel to join in and share your comments and questions both with us and in the comments section below. Our commentary begins after the jump: