Ben Roethlisberger threw for 253 yards and two touchdowns, rookie Najee Harris ran for a career-best 122 yards and the Pittsburgh Steelers beat the Denver Broncos 27-19 on Sunday to snap a three-game losing streak.

Riding the kind of balance that's been rare during a sluggish opening month, the Steelers handed the Broncos (3-2) a second straight loss.

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Denver fell behind by 18 points in the third quarter before rallying behind quarterback Teddy Bridgewater, who started after spending the week in the NFL's concussion protocol. Bridgewater completed 24 of 38 passes for 288 yards and two fourth-quarter touchdowns. He led Denver inside the Pittsburgh 10 in the final minute, but his fourth-down pass attempt in the back of the end zone to Courtland Sutton was picked off by James Pierre.

The loss made Denver’s perfect September look more like a mirage. The Broncos piled up wins against the New York Giants, Jacksonville and the New York Jets last month. Tested by Baltimore and Pittsburgh in back-to-back weeks, the Broncos came up short.

Denver's pass rush failed to produce much against Pittsburgh's struggling offensive line and with Harris giving the NFL's worst rushing offense some life — his 100-yard game was the first by a Steelers running back in nearly a year — offensive coordinator Matt Canada's playbook finally opened up.

Roethlisberger, who entered Sunday as the league's 27th-rated quarterback while weathering questions about whether he can still be effective in his 18th season, was the beneficiary.

The 39-year-old was sacked just once and completed 15 of 25 passes, including a 50-yard touchdown to Diontae Johnson and an 18-yard score to Chase Claypool that gave the Steelers a seemingly comfortable 24-6 lead with 2:41 to go in the third quarter.

Bridgewater finally started to find a rhythm, finding Kendall Hinton for a 2-yard score and lobbing a rainbow down the left sideline that a diving Sutton snagged as he crossed the goal line to get the Broncos within five.

It just wasn't enough on a day Denver missed a handful of opportunities to flip momentum.

Three times the Broncos appeared to have their hands on an interception only to have the ball fall harmlessly to the turf. Running back Javonte Williams ripped off a 49-yard run only to spike the ball after getting tackled at the Pittsburgh 1. The act drew a delay-of-game penalty and the Broncos ended up settling for a field goal.

A pass-interference penalty on Kyle Fuller set up Harris' 1-yard dive and a rare "leverage" penalty on a Pittsburgh field-goal attempt instead gave the Steelers a first down. Three plays later, Roethlisberger connected with Claypool to give the Steelers an 18-point lead and a bit of peace following a tumultuous stretch.

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INJURIES

Broncos: Cornerback Mike Ford (knee) left in the second half and did not return.

Steelers: Lost wide receiver JuJu Smith-Schuster with a shoulder injury in the second quarter after getting tackled following a 3-yard gain on an end-around. ... Inside linebacker Devin Bush left in the third quarter with an unspecified leg injury. ... Harris departed late with a cramping issue.

UP NEXT

Broncos: Begin AFC West play next week when they host the Las Vegas Raiders. Las Vegas swept the season series last year.

Steelers: Host the Russell Wilson-less Seattle Seahawks (2-3) next Sunday night. The Seattle star QB is out at several after undergoing surgery on his right middle finger last Friday. Geno Smith is expected to start in Wilson's place.