INGLEWOOD, Calif. (Interstat) — In a stunning overtime upset that defied statistical projections, the San Francisco 49ers edged the Los Angeles Rams 26-23 on Thursday night at a sold-out SoFi Stadium.

The 49ers, who entered the game as 8.5-point underdogs and were given just a 15.5 percent chance to win by one analytics system, improved their record to 4-1. The Rams fell to 3-2.

San Francisco quarterback Mac Jones orchestrated the victory, completing 33 of 49 passes for 342 yards and two touchdowns. His favorite target was Kendrick Bourne, who hauled in 10 catches for 142 yards. The 49ers’ offense, however, ran through Christian McCaffrey, who scored two touchdowns — one rushing, one receiving — and tallied 139 all-purpose yards.

The game was a tale of two halves and a dramatic comeback. The 49ers dominated early, marching down the field on their opening possession and capping the drive with a 6-yard touchdown pass from Jones to tight end Jake Tonges. They extended their lead to 14-0 early in the second quarter on a 1-yard scoring pass to McCaffrey.

After the Rams got on the board with a 14-yard touchdown pass from Matthew Stafford to Kyren Williams, the 49ers added a 37-yard field goal from Eddy Pineiro as time expired in the first half to take a 17-7 lead into the break.

The Rams began to claw back in the third quarter. Following a 20-yard field goal by Pineiro, Los Angeles answered with a methodical drive finished by a 1-yard touchdown catch by Puka Nacua from Stafford, cutting the deficit to 20-14.

The fourth quarter saw the Rams complete their comeback. Stafford connected with Williams for another touchdown, but a blocked extra point left the score at 20-20. San Francisco responded by retaking the lead with a clutch 59-yard field goal from Pineiro with just 2:52 remaining, a career-long kick that cleared the crossbar with room to spare.

With no timeouts and 42 seconds left, Stafford engineered a final drive to set up Joshua Karty for a 48-yard field goal as time expired in regulation, sending the game to overtime tied at 23.

In the extra period, the 49ers’ offense methodically moved into field goal range. A key sack by the Rams’ defense, split by Byron Young and Kobie Turner, pushed San Francisco back, but Pineiro was true again from 41 yards out to put the 49ers ahead.

The Rams had a chance to answer, quickly moving into 49ers territory on a 38-yard deep shot from Stafford to Tutu Atwell. But the drive stalled at the San Francisco 11-yard line, and on a critical fourth down, Williams was stopped for no gain by a swarming 49ers defense, sealing the victory for the visitors.

Stafford finished with strong numbers, completing 30 of 47 passes for 389 yards and three touchdowns. Williams was a dual-threat force for the Rams, rushing for 65 yards and adding 66 receiving yards with two touchdown catches. Nacua caught 10 passes for 85 yards and a score.

Defensively, the Rams were led by linebacker Nate Landman, who recorded a game-high 14 tackles. Safety Quentin Lake added 11 tackles. For the 49ers, safety Marques Sigle had 13 tackles and linebacker Fred Warner was in on 12.

The announced attendance was 73,652. The total points scored, 49, went under the betting over/under line of 43.5.

San Francisco travels to Tampa Bay next on Oct. 12. The Rams will face the Baltimore Ravens on the same day.