Ruiz opened Philadelphia's account in the 27th minute, converting a tap-in goal from the edge of the six-yard box. After Kyle Nakazawa found Justin Mapp along the right flank, Mapp sent a cross into the box, where "El Pescadito" was able to calmly convert for a 1-0 advantage.
The Union nearly took a 2-0 lead in the 36th minute after Roger Torres was fouled 30 yards out, but Ruiz's free kick from distance was denied by the opposing 'keeper.
Ergotelis threatened to equalize in the 39th minute after a foul outside Philadelphia's box yielded a dangerous free kick, but goalkeeper Faryd Mondragón was able to deflect an attempted shot wide of the post.
The Union controlled possession for much of the second half, but the visiting side generated their first legitimate scoring opportunity in the 76th minute. Nakazawa's service from the flank targeted Jack McInerney and Zach Pfeffer in the area, but the youngsters were unable to convert an insurance goal for Philadelphia.
Ergotelis found their equalizer after Stefani Miglioranzi was whistled for a foul in the box, leading to a dramatic 88th minute penalty kick. 19-year-old Nikos Karelis stepped up to the spot and converted past rookie 'keeper Zac MacMath to tie the score at one goal apiece.
Ryan Richter had an opportunity to give the Union a last-second victory, but the supplemental draft pick missed a header on an open goal in injury time.
Philadelphia Union will return to action on March 2, as Peter Nowak's side will face Greek Third Division side Hersonissos F.C. at Pancretan Stadium. The Union's final leg of preseason training, sponsored by Colonial Marble & Granite, will run until March 10.
PHI ? Carlos Ruiz (Justin Mapp, Kyle Nakazawa) 27'
ERG ? Nikos Karelis (Penalty Kick) 88'
(Copyright 2011 Philadelphia Union. Reprinted by permission)