DENVER -- As far as exhibition tests go, facing Peyton Manning has to be among the most challenging – especially in the dress rehersal that is Week 3 of the preseason.

The San Francisco 49ers defense rose to that occasion on Saturday night, limiting Manning and the Denver Broncos high-powered offense to just two field goals in the first half.

The 49ers wound up falling to the Broncos, 19-12, at Sports Authority Field, but the first-team defense certainly stood out as a bright spot.

NaVorro Bowman, in his second game action, led the charge with nine first-half tackles, including two sacks of Manning. The linebacker sure looked like his All-Pro self, consistently applying pressure in the Denver backfield.

In all, the 49ers tallied four tackles for loss, three sacks and an interception while Manning was in the game. Not bad for a preseason tuneup.

In case you missed Saturday's contest, catch up on what else transpired in the victory/loss below.

Play of the Game

Kenneth Acker, starting in place of Tramaine Brock (muscle strain), halted a second quarter Broncos drive into 49ers territory by intercepting Manning in the end zone.

The second-year cornerback successfully boxed out Pro Bowl wide receiver Demaryius Thomas to pick off the underthrown attempt from the future Hall of Famer. Acker missed all of 2014 recovering from a foot injury but has performed well throughout the preseason.

Scoring Rewind

The Broncos got on the board first, driving 14 plays on their second offensive possession of the night. Dontae Johnson, lining up outside in nickel packages, prevented a long Manning touchdown pass by breaking up a throw intended for star wideout Thomas in the end zone. Denver settled for a 34-yard Brandon McManus field goal to go ahead, 3-0, midway through the first quarter.

Demarcus Ware added to the Broncos lead early in the second when he sacked Colin Kaepernick in the end zone for a safety. Later in the quarter, the Broncos had a 1st-and-goal from the 5-yard line, but as the San Francisco defense did throughout the first half, it held Manning and Co. out of the end zone. On the third-down play, rookie safety Jaquiski Tartt levied a quarterback hit on Manning to force a quick throw into the end zone. Acker completed the stop by knocking the pass away from Cody Latimer. McManus converted the short field-goal attempt for an 8-0 lead. 

The 49ers snapped their scoring drought just before halftime, executing their two-minute offense by marching 57 yards in 1 minutes and 32 seconds to put Phil Dawson in position for a 41-yard field goal, which he drilled. Colin Kaepernick led the offense on the drive with two long runs, one for 19 yards and the other for 34 yards. 

Trailing 8-3 at the half, the 49ers scored twice in the third quarter, both on Blaine Gabbert-led drives ending in Corey Acosta field goals. Those gave San Francisco a 9-8 lead heading into the final period. 

In the fourth, the teams exchanged another field goal each, McManus' coming from 45 yards out and Acosta's from 29 yards away.

The Broncos won the game on a 1-yard Juwan Thompson touchdown run with just over two minutes remaining in regulation. 

How the Starters Fared

Kaepernick played the entire first half, completing 2-of-5 passes for 13 yards. The quarterback, as mentioned above, made his biggest contributions on the ground with 53 rushing yards.

Pierre Garçon continued to shine as San Francisco's lead 'back, tallying 28 yards on four carries. The second-year ball carrier delivered a highlight-reel run midway through the second quarter, using a terrific spin move to escape a Broncos linebacker and break into the secondary for a 17-yard gain. 

Also in the backfield, Reggie Bush made his team debut, and looked strong with the rock. The veteran's first two carries went for nine and 22 yards, respectively.

Torrey Smith caught his first pass in a 49ers uniform, hauling in a short throw from Kaepernick in the red zone.

On defense, Bowman was again the headliner. A week after tallying three tackles in three snaps versus the Dallas Cowboys, Bowman led San Francisco in tackles against Denver with nine, including seven solo. The veteran, coming off a year-and-a-half long rehab from a knee injury, amassed that production all in the first two quarters. 

Keith Reaser, another second-year cornerback who sat out his rookie season due to injury, turned in a solid night with three tackles, including one for loss.

Michael Wilhoite and Corey Lemonier combined for nine more tackles. One of Lemonier's went for a sack of Manning.

Darnell Dockett deflected a Manning pass at the line of scrimmage and nearly came down with the ball for an interception. 

Rookie Watch

Mike Davis rushed for 28 yards on eight carries. Jarryd Hayne 

Blake Bell caught three passes for 19 yards and DeAndrew White added one for eight yards. 

Tartt had a tackles for a loss and a quarterback hit while Eli Harold amassed four tackles.

First-rounder Arik Armstead received first-team reps in the first half, but he did not get on the stat sheet. 

Acosta finished his night 3-for-3 on field goals.

Jarryd Hayne caught one pass for 18 yards, had a 12-yard punt return and was credited for a tackle on special teams.

Up Next

The 49ers return home to close out the exhibition season on Thursday versus Philip Rivers and the San Diego Chargers. Before that, however, the team must cut its roster down to 75 players by 1 p.m. PT on Tuesday. Stay tuned to 49ers.com for complete coverage throughout the week as San Francisco begins to put in its final preparations for the regular season.