TAMPA, Fla. >> Christian McCaffrey’s season debut was a mere afterthought once the 49ers finished up a 23-20 victory Sunday over the Tampa Bay Bucs.

Brock Purdy engineered a last-minute drive that left it up to Jake Moody, who made a 44-yard field goal as time expired to atone for three earlier misses.

Moody was mobbed by teammates as the 49ers improved to 5-4 on the season.

Walking by without immediately congratulating him, however, was Deebo Samuel. After Moody’s third missed field goal of the day, Samuel confronted him near the 49ers sideline, long snapper Taybor Pepper intervened, Samuel’s left hand took a swipe into Peppers’ throat, and coaching assistants intervened to separate them.

It didn’t have to be such a close game, only it was as the 49ers defense failed to hold a fourth-quarter lead and earlier special teams miscues opened the comeback door for Tampa Bay (5-5).

Purdy completed all four of his passes on the winning drive, with two targets apiece to Jauan Jennings and Ricky Pearsall.

Earlier in the fourth quarter, Purdy threw an 11-yard touchdown pass to George Kittle in the back left corner of the end zone to give the 49ers a 20-17 lead midway through the fourth quarter against the undermanned but gritty Bucs. Purdy scrambled around this Florida swampland before eventually throwing to a familiar spot, where Kittle also made a remarkable touchdown grab in the 49ers’ Sept. 29 win over New England.

The 49ers let another fourth-quarter lead slip away this season, however, as the Bucs pulled even at 20 on a last-minute, 26-yard field goal from Chase McLaughlin. Keying that drive were a dumbfounding barrage of defensive penalties, on Rock Ya-Sin (holding), Fred Warner (facemask), Maliek Collins (roughing the passer), and Evan Anderson (illegal hands to the face).

McCaffrey’s season debut undoubtedly enhanced the 49ers’ offense, as he totaled 68 receiving yards (six catches) and just 39 rushing yards (13 carries). Purdy passed for 353 yards and two touchdowns with no turnovers, while Baker Mayfield had just 116 yards for the Bucs.

The Bucs had their own say, primarily with their running backs leading their undermanned offense. Bucky Irving opened the fourth quarter with a 14-yard run on third-and-2, then followed that with a 12-yard touchdown dash past six defenders for the Bucs’ first lead of the game, 17-13.

The home crowd chanted “Buck-eee!” as the rookie rusher had 75 yards to that point. Fellow Bucs running back Raachad White scored Tampa’s first touchdown in the preceding quarter on a 9-yard catch-and run.

Pearsall’s first career touchdown put the 49ers ahead 7-0, once a replay confirmed Pearsall’s 56-yard catch-and-run. Pearsall caught Purdy’s pass in stride over the middle at the Bucs’ 30, then beat safety Antoine Winfield Jr. to the left pylon.

Pearsall celebrated with Jauan Jennings in a choreographed dance, then was handed back the souvenir football from fullback Kyle Juszczyk as more teammates happily mobbed him.

That initial scoring drive was kept alive by a third-down holding penalty on the Bucs.