Cincinnati had the ball at its own five-yard line with just over two minutes remaining in the game and rookie quarterback Andy Dalton showed poise as he led the offense as far as Denver's 48-yard line.
Facing a 2nd-and-10, Dalton was sacked and then threw an incompletion on third down, leaving the Bengals with a 4th-and 19 play and under a minute remaining.
Dalton's final pass also fell incomplete and the Broncos held on for the win.
"It's one of the best wins I've ever been a part of, and I've been a part of a lot of them," Orton said. "This is a great win to battle the way we did. The defense played great, we ran the football great and made enough plays in the passing game to get the win."
Dalton had an outstanding day in defeat, throwing for 332 yards and two touchdowns for the Bengals (1-1). Rookie A.J. Green caught 10 passes for 124 yards and a touchdown and Cedric Benson rushed 16 times for 59 yards.
"It doesn't really matter what I did," Dalton said. "We had a chance, we were in it right to the end but we have to do a better job of executing when it matters."
Denver received the opening kickoff and wasted little time jumping out to a 7-0 lead. Orton led the offense on a 15-play, 80-yard drive down to the Bengals' one-yard line before McGahee pounded it into the end zone.
Midway through the second quarter, Cincinnati got on the board after Decker fumbled and the Bengals recovered the ball on the Denver 41-yard line. Dalton took the Bengals down to the 14-yard line and Mike Nugent connected on a 45- yard field goal to get the Bengals within 7-3.
The Broncos extended their lead to 10-3 when Matt Prater nailed a 34-yard field goal in the dying seconds of the first half.
Coming out of the break, Cincinnati went three-and-out and Denver struck again on its first possession of the second half. Starting from its own 41, the Broncos offense moved down the field with ease and Orton found Decker for a 25-yard strike to make it 17-3.
On the Bengals' ensuing possession, Dalton found Green deep over the middle for a completion of 26 yards. They continued to march down to the Denver 19- yard line and Nugent connected on a 37-yard field goal attempt to make it 17-6.
With 3 1/2 minutes remaining in the third quarter, Dalton found Andre Caldwell in the end zone to cap a six-play, 72-yard march. Cincinnati then went for the two-point conversion to make it a three-point game, but Dalton's pass was knocked away.
Nugent converted another field goal, this time from 23 yards out, to close out the third quarter and pull Cincinnati within 17-15.
Early in the fourth, Denver extended its lead when Orton connected with Decker on a 52-yard touchdown strike, capping a quick five-play, 80-yard drive to give Denver a 24-15 advantage.
On the first play of the ensuing Bengals drive, Dalton was sacked for a loss of 13 yards, but bounced back on the next play, finding Jerome Simpson down the middle with a deep bomb for 84 yards. The completion took the offense down to the Denver nine-yard line and Dalton hit Green two plays later for a five- yard touchdown strike to account for the final margin.
Denver leads the all-time series with Cincinnati, 18-8...Broncos head coach John Fox is 2-2 in his career against the Bengals, while Bengals coach Marvin Lewis is 1-4 against Denver...Denver was 5-for-12 on third down, while Cincinnati converted only one third down in 11 tries.