After four quarters of play at Mile High Stadium, the Pittsburgh Steelers and Denver Broncos are headed to overtime in the NFL's first extra session since instituting new overtime rules this offseason.

With the new rules, unless the team that receives the ball first scores a touchdown, the other team will have a chance to answer. Hypothetically, if the Steelers win the coin toss and kick a field goal, the Broncos would be given one chance to drive the field and kick a field goal to tie it or even win it with a touchdown.

If the teams are even after their first possession, the game becomes the sudden death session that most NFL fans are accustomed to.

This is the first non-sudden death overtime in the NFL's history, played between two teams that went to the first regular season overtime in 1974.

For updates, stay tuned to SB Nation Pittsburgh. For more in-depth coverage of Pittsburgh vs. Denver, visit Steelers blog Behind the Steel Curtain and Broncos blog Mile High Report. For more news and notes from around the NFL, visit SB Nation's NFL news hub.