Josh Scobee's dramatic field goal gave Jacksonville a 31-29 win at Pittsburgh in the wildcard round of the play-offs.
Scobee's goal ensured Pittsburgh paid for their poor kicking
The Jaguars led 28-10 but Pittsburgh scored two fourth-quarter touchdowns to grab a 29-28 lead in the AFC encounter.
But Jacksonville quarterback David Garrard ran 32 yards on the fourth down to set up Scobee's last-minute chance.
Marcus Trufant and Jordan Babineaux returned fourth-quarter interceptions for touchdowns to give Seattle a 35-14 win over Washington in the NFC game.
Jacksonville now face a game with New England or Indianapolis, while the Seahawks advance to a second-round play-off at Green Bay next week.
Pittsburgh struck first against the Jaguars, with Najeh Davenport going over at the end of a 10-play drive but the visitors responded immediately.
Maurice Jones-Drew's 96-yard kick-off return left Fred Taylor with just one yard to make for their opening touchdown, and two more in the second quarter by Rashean Mathis and Jones-Drew put the Jaguars in control.
Jeff Reed's field goal kept the Steelers in touch but when Jones-Drew ran in his second score, the Jaguars looked comfortable.
Touchdowns by Santiago Holmes, Heath Miller and Davenport brought Pittsburgh back into the game the final quarter but they only managed to add the two points after from one of those kicks.
And when Scobee struck, that failure to score proved their undoing.
Matt Hasselbeck had given the Seahawks the lead with a touchdown pass to DJ Hackett but the Redskins were driving when Trufant picked off a long Todd Collins throw and ran it back to the end zone with five minutes and 39 seconds remaining.
With the Redskins desperate in the final seconds, Collins was picked off against by Babineaux, who ran back the interception 57 yards for the clinching touchdown with 27 seconds remaining.
New York Giants face Tampa Bay Buccaneers and Tennessee Titans take on San Diego Chargers in Sunday's matches.