SANTA CLARA, Calif. >> Rookie Brock Purdy threw two touchdown passes after replacing an injured Jimmy Garoppolo and the San Francisco 49ers used another dominant defensive performance to beat the Miami Dolphins 33-17 Sunday for their fifth straight win.

Garoppolo has a broken foot and will miss the rest of the season, coach Kyle Shanahan said after the game.

The 49ers (8-4) allowed a 75-yard touchdown pass to Trent Sherfield on the opening play from scrimmage but little else until the fourth quarter against a high-powered attack for Miami (8-4) which had scored at least 30 points in four straight games.

Jimmie Ward and Deommodore Lenoir intercepted Tua Tagovailoa in the third quarter, leading to two field goals.

The 49ers had their four-game, second-half shutout streak snapped when Tagovailoa threw a 45-yard TD pass to Tyreek Hill in the opening minute of the fourth quarter but held on from there. They capped the performance with a strip-sack from Nick Bosa that Dre Greenlaw returned for a 23-yard score.

The Dolphins had their five-game winning streak snapped in coach Mike McDaniel’s first game against the 49ers after spending the past five years as an assistant in San Francisco.

Purdy, dubbed “Mr. Irrelevant” as the last pick of this year’s NFL draft, proved to be quite important to the 49ers when Garoppolo hurt his foot on a sack on the final play of the opening drive.

Garoppolo was taken to the locker room on a cart and didn’t return, leaving the game in the hands of Purdy, who had thrown his only nine passes in mop-up duty of a Week 7 loss to Kansas City.

Purdy capped his first drive of the game by throwing a 3-yard TD pass to Kyle Juszczyk to give San Francisco a 10-7 lead.

He then led a well-executed two-minute drive at the end of the half, completing six passes for 75 yards with a 3-yard TD to Christian McCaffrey with 4 seconds left in the half to make it 17-10.

Purdy finished 25 for 37 for 210 yards, two TDs and one interception.

CHALLENGE

Shanahan won two challenges in the fourth quarter to overturn completed passes by Miami. The second came on a fourth-and-2 play with the Niners leading by six with about six minutes left.

The Niners held the ball for nearly four minutes and made it a two-score game when Robbie Gould kicked a 48-yard field goal for his fourth of the day.

FAST START

The Dolphins wasted little time showing off their speed when Tagovailoa connected on the long touchdown to Sherfield on the first play from scrimmage.

It marked the first time a team scored on the first play after the opening kick since the Niners did it in Week 2 of the 2020 season against the Jets with an 80-yard run by Raheem Mostert.

The touchdown ended a scoreless streak of more than 94 minutes for the 49ers, who hadn’t allowed a point since the second quarter against Arizona two weeks ago.

Miami hadn’t scored a TD on the first play from scrimmage following the opening kick since the final game of the 2004 season when Sage Rosenfels threw a 76-yard pass to Chris Chambers against Baltimore.

INJURIES

Dolphins: WR Jaylen Waddle left in the first half with a leg injury but returned to the game.

49ers: San Francisco already lost starting QB Trey Lance to a season-ending ankle injury in Week 2. The only other QB under contract is Jacob Eason, who is on the practice squad. … DT Hassan Ridgeway (pectoral) left in the fourth quarter and didn’t return.

UP NEXT

Dolphins: Visit Chargers on Sunday night.

49ers: Host Tampa Bay on Sunday.