Coming off their Monday night home win over the Panthers, the Cowboys flew to Invesco Field at Mile High for a Week 4 interconference duel with the Denver Broncos.  Dallas would deliver the opening shots in the first quarter with kicker Nick Folk making a 49-yard field goal, followed by running back Marion Barber's 1-yard touchdown run.  The Broncos would answer in the second quarter with quarterback Kyle Orton completing a 9-yard touchdown pass to running back Knowshon Moreno.  After a scoreless third quarter, Denver would take control in the fourth.  The Broncos would tie the game with a 28-yard field goal from kicker Matt Prater, and then they would take the lead with Orton's 51-yard touchdown pass to wide receiver Brandon Marshall.  The 'Boys would get a late game drive all the way down to Denver's 1-yard line, but the Broncos' defense would hold on for the win.. How many yards was the longest touchdown play?