SANTA CLARA, Calif. — Maybe the premature boasts of grandeur can stop now.

The Broncos need to stop talking Super Bowl. They can pick it back up in early-January if they’re so inclined but there is no way a bunch of first-stringers who got whipped by a team of San Francisco second-stringers should be thinking about anything but the ego-check they took here in the preseason opener on a hot, sunny Saturday evening at Levi’s Stadium.

With the Broncos’ first-stringers getting outscored, 9-0 in the first quarter, No. 2 quarterback Jarrett Stidham and the Broncos’ backups rallied in the second quarter to give the all-white-clad visitors a 20-9 lead at halftime.

Sean Payton, the Broncos’ head coach, has been good at instilling swagger into his team the past two years but he went a step further last week by publicly pronouncing his team as being good enough to have a chance to win the Super Bowl. Which is fine except that pronouncement grew legs to the point everyone in Broncos Country and the NFL media has been running with it.

Enough with such chatter.

After a lengthy 2 ½-hour joint practice with the San Francisco 49ers on Thursday, Payton sent his first stringers back out there to play in the preseason opener two days later. 49ers coach Kyle Shanahan, though, thought the joint practice was enough and had top guys Brock Purdy, George Kittle and Nick Bosa cheering from the sidelines in T-shirts and sweats.

After two series, the 49ers were up 9-0.

The much-hyped Denver D, playing without injured inside linebackers Alex Singleton and Dre Greenlaw, surrendered a 71-yard touchdown drive on the opening series. San Francisco backup quarterback Mac Jones was 3 for 3 for 64 yards on the game-opening drive, including a 50-yard completion to Jordan Watkins, who beat Denver nickelback Ja’Quan McMillian.

Meanwhile, San Francisco’s No. 2 defense got 2 points off Bo Nix and the Broncos’ first-string offense. Robert Saleh, back as the 49ers’ defensive coordinator after an unsuccessful head coaching stint with the Jets, sent cornerback Chase Lucas in on a blitz on a third-and-6 from the 14. Nix reverse pivoted in retreat but that put him midway into his own end zone. He attempted to throw the ball away but it was in the wrong spot to do it.

Intentional grounding from the end zone, safety. The Broncos were down, 9-0.

Payton was so flummoxed he sent his first-team offense back out for a third series. A McMillian redemptive interception off Jones set up a short field for the offense. The Broncos moved it only 26 yards, but enough for a Wil Lutz 42-yard field goal.

It was backups against backups from there and that’s when the Broncos took complete control. Stidham, in his seventh season as a backup QB, led a 13-play drive for a field goal highlighted by his 18-yard scramble and 12-yard completion to rookie receiver Pat Bryant. Stidham later connected with tight end Lucas Krull for an 8-yard touchdown to give Denver a 13-9 lead with 1:30 left in the first half.

The Denver D forced a quick three-and-out against the 49ers’ third stringers and Stidham got the ball back, thanks in part to Payton using timeouts to stop the clock. Stidham hit Trent Sherfield Sr., perhaps the Broncos’ most underrated free-agent acquisition this offseason, with back-to-back passes of 19 yards and 36 yards for a touchdown.

Stidham was 12 of 13 for 120 yards and two touchdowns for a 144.7 passer rating in about a quarter’s worth of play. Backup running back Tyler Badie had 32 yards rushing off five carries. Sherfield had the three catches for 73 yards and a touchdown. Undrafted rookie inside linebacker Karene Reid made an impressive interception over the middle to set up another short-field possession.

For the first teamers. Nix finished 6 of 11 for just 31 yards. Rookie running-back RJ Harvey started and rushed for 25 yards on 7 yards. Troy Franklin continued his strong offseason/training camp/preseason with three catches for 18 yards.

Among the Broncos nicked up and didn’t play Saturday: Fullback Michael Burton, tight end Nate Adkins, receiver Joaquin Davis and inside linebackers Alex Singleton and Dre Greenlaw. …

The Broncos will finish training camp for the fans this week with practices Tuesday and Wednesday, then a joint practice Thursday with the Arizona Cardinals at Broncos Park. Each practice begins at 10 a.m. …

Denver’s Nik Bonitto and John Franklin-Myers came on in the second defensive series and each recorded a sack against Mac Jones.