Philadelphia Union advanced to the CONCACAF Champions League semi-finals on Wednesday after two crucial VAR decisions handed the Major League Soccer side a 2-2 draw against Mexico's FC Atlas. 

They set up a last-four clash with Los Angeles FC after two goals from Julian Carranza secured a 3-2 aggregate victory after 1-0 win in the first leg. 

Both of Carranza's goals were given despite being initially flagged for offside. 

VAR overturned both decisions in Philadelphia's favour to secure a famous result for Jim Curtin's side. 

Julian Quinones got Atlas off to a dream start after just 11 minutes, Jonathan Herrera laying off to the Colombian striker to rifle home a low shot from just inside the area. 

But Carranza put Philadelphia ahead 2-1 on aggregate with a brilliantly worked equalizer in the 28th minute. 

A clever lofted pass from Jack McGlynn found the Argentine in the area and the South American controlled deftly before prodding a finish past the advancing Atlas goalkeeper Jose Hernandez. 

Carranza looked well onside, but the referee's assistant flagged for offside before VAR's intervention awarded the goal to Philadelphia. 

The crucial away goal meant that Atlas would have to score twice to advance, and they got one of them just before half time when Julio Furch tapped in from close range after a well-worked move. 

Yet Philadelphia's defense held firm throughout the second half and then in the 78th minute Carranza grabbed his second after a swift counterattack. 

Again, though, the Argentine was flagged for offside -- and once again the decision was overturned to leave Philadelphia 3-2 ahead on aggregate. 

That left Atlas needing to score twice in the closing minutes, which never looked on the cards. Atlas's frustration mounted and Aldo Rocha was sent off for dissent as tempers flared. 

Philadelphia's victory means Union will face Los Angeles in a replay of last year's classic MLS Cup final, won by LAFC on penalties after a dramatic 3-3 draw.