SAN FRANCISCO -- Kyle Orton threw interceptions in his first three series during a disastrous Denver debut, while San Francisco's two quarterback candidates were steady in the 49ers' 17-16 victory over the Broncos on Friday night.
Alex Smith threw a 3-yard touchdown pass to Brit Miller following Orton's third first-half pick in the exhibition opener for both teams, a night featuring the returnof former 49ers coach Mike Nolan as Denver's defensive coordinator.
San Francisco starter Shaun Hill completed two crisp passes to tight end Vernon Davis for 41 yards while leading the Niners on a 58-yard scoring drive to start the game, capped by Alex Romero's 38-yard field goal.
It was Orton's backup, Chris Simms, who nearly led Denver to victory with a big second half. After Miller's second TD of the night on a 40-yard reception from Damon Huard put the 49ers up 17-10, Simms hit Kenny McKinley on a 52-yard TD pass with 2:01 left, but the Broncos failed on the 2-point conversion.
New Broncos coach Josh McDaniels is stressing accuracy this training camp, and Orton was way off all night against the Niners' first- and second-team defenses. Even with ample time in the pocket, he misfired.
Orton got the No. 1 job in June but has done little to impress after the Broncos traded away Pro Bowl passer Jay Cutler to the Chicago Bears in the NFL's biggest swap of the spring. Orton was even booed by fans during a scrimmage at Invesco Field when he threw two interceptions and several other poor passes.
He completed six of his first seven passes for 54 yards Friday but couldn't capitalize.
Everybody's curious to see how Orton handles the pressure and responsibility for an organization that's won just one playoff game since Hall of Famer John Elway retired with two Super Bowl titles a decade ago.
San Francisco cornerback Nate Clements was constantly in the middle of the action. He had four solo tackles and an interception on Denver's first drive, picking off a pass from Orton in the end zone intended for Daniel Graham on third-and-goal from the 3.
"I saw the route and played my responsibility and he threw it," Clements said. "I like seeing all of our (defensive backs) get interceptions and just making plays because we're game breakers."
Neither Hill nor Smith did anything flashy to stand out -- not that coach Mike Singletary expected to have a good gauge of who might be his top QB after just one preseason game. He hadn't decided on a starter for the second preseason game, next Saturday against the Oakland Raiders.
Hill went 2 for 2 with the two completions to Davis and was sacked twice, while Smith was 5 of 7 for 33 yards with a sack.
"We were able to move the ball and we had a big conversion on third down," Hill said. "That last sack kind of hurt us. That was completely on me. The offensive line did a great job out there. So I'd like to have that play back and I feel like we could have gotten seven out of that."
With Orton long gone, Jeb Putzier caught a 6-yard TD pass from Simms midway through the third quarter. Simms later hit Brandon Lloyd for a 25-yard completion that set up Matt Prater's go-ahead 26-yard field goal.
McDaniels certainly had hoped for more from Orton. He came to the Broncos after Cutler decided he didn't want to play for McDaniels, the former offensive coordinator and quarterbacks coach in New England.
Hill went 5-3 over the final eight games last season, when Singletary took over Oct. 20 and later had the interim tag stripped from his title following the team's strong finish.
Smith missed all of 2008 after re-injuring his surgically repaired right shoulder in practice two days before the season opener.
"Obviously, I was raring to go when I got out there," Smith said. "It's been a long time for me, so I was pretty amped up."
Singletary is eager to name a starter who can turn around a team that's endured a franchise-worst six straight losing seasons, yet he's said he might wait until after the third preseason game.