OAKLAND, Calif. – The Steelers defense allowed a 75-yard drive and a touchdown with 21 seconds left and then Chris Boswell slipped and missed a 40-yard field goal with no time left to ruin Ben Roethlisberger’s dramatic comeback in a 24-21 loss to the Oakland Raiders Sunday.

Derek Carr threw a six-yard touchdown pass on fourth down to Derek Carrier to send the Steelers’ to their third straight loss and a 7-5-1 record. The Raiders are 3-10.

But with 15 seconds left after the kickoff, Roethlisberger completed a nine-yard pass to James Washington, who pitched it back to JuJu Smith-Schuster, who ran to the Raiders 30 and out of bounds.

Boswell, who missed a field goal earlier, lined up to tie the game but instead slipped as he approached the ball to end the game.

Roethlisberger returned late in the fourth quarter from a rib injury to dramatically guide the Steelers to a 21-17 lead with 2:55 left.

Roethlisberger’s ribs were injured in the first half and he did not come out of the locker room until midway through the third quarter, then stood on the sideline wearing a baseball cap as Josh Dobbs took over at quarterback.

However, Roethlisberger returned with 5:20 left after Oakland went ahead 17-14. He completed all six of his passes for 70 yards, including one-yard touchdown pass to JuJu Smith-Schuster with 2:55 left in the game.

The only other play on that drive was a five-yard holding penalty against Oakland.

The Raiders had taken a three-point lead on Derek Carrk’s 3-yard touchdown pass to tight end Lee Smith. It was the 14th play of a 73-yard drive that featured three third-down conversions and one on fourth-down.

Roethlisberger did not play in the third quarter because of his rib injury as the Steelers held on to a 14-10 lead entering the final quarter against the Oakland Raiders.

It was the two teams’ defenses that came up with the biggest plays of the quarter. Oakland quarterback Derek Carr had the ball slip out of his hands while trying to pass from the Steelers’ 22. Cornerback Mike Hilton recovered at the 16 to end that threat.

However, on that series, Dobbs threw a pass to Antonio Brown that was tipped by cornerback Gareon Conley and intercepted by linebacker Tahir Whitehead at the Steelers’ 44 with 12 seconds left in the third quarter.

Roethlisberger may have been injured while he was sacked in the second quarter by defensive tackle Clinton McDonald.

The Steelers scored two touchdowns in the second quarter for a 14-10 halftime lead.

The Steelers grabbed their first lead with 10 seconds left in the half on JuJu Smith-Schuster’s toe-tapping touchdown catch in the back of the end zone that would do Antonio Brown and Santonio Holmes proud.

The one-yard pass from Roethlisberger was ruled incomplete but overturned via replay. Smith-Schuster’s 20-yard back-shoulder catch along the right sidelines breathed early life into that successful 53-yard drive.

The Steelers had tied it 7-7 early in the second quarter on Stevan Ridley’s two yard run up the middle from the I-formation behind fullback Roosevelt Nix.

Nix was on the sideline when Roethlisberger ran over to the coaches during a time out to suggest otherwise. Antonio Brown and tight end Xavier Grimble came off the field and Nix and tight end Vance McDonald came on.

Rookie Jaylen Samuels had started at halfback for the injured James Conner but Mike Tomlin said he would use a back-by committee that would include Ridley, who entered the game during that scoring drive, the Steelers second series of the game.

The Raiders reached the Steelers’ 26 on their next drive and went back on top 10-7 on rookie Daniel Carlson’s 44-yard field goal. Mike Hilton dropped an interception thrown right to him after a receiver slipped on the previous third-down play, another missed turnover opportunity for the Steelers.

And speaking of missed opportunities, Chris Boswell missed another kick, this one a field goal try from 39 yards that went wide right, preserving Oakland’s 10-7 lead. Boswell, who has missed five PAT kicks, is 10 of 15 on field goal tries after that miss.

Oakland scored on the first series of the game to take a 7-0 lead.

The Raiders took the opening kickoff and in eight plays led 7-0 on Doug Martin’s one-yard dive over the middle. Derek Carr completed consecutive passes of 29 and 19 yards to tight end Jared Cook early in that series.