Unlike their previous two wins, the 49ers didn’t need a riveting comeback Sunday. Instead, they needed a history book to put in perspective their 48-3 annihilation of the Tampa Bay Buccaneers at Candlestick Park.

It was the 49ers’ most lopsided regular-season win since a 48-0 shutout of the Los Angeles Rams in 1987. It also improved the 49ers to 4-1 for the first time since 2002, their last playoff campaign.

“It’s just a fun time right now,” said left guard Adam Snyder, a seventh-year veteran. “When the defense does something good, everybody is on the field celebrating. When the offense does good, everyone is high-fiving.”

“It’s the first time since I’ve been here that we are looking this good,” added running back Frank Gore, who had 20 carries for 125 yards and a touchdown.

The 49ers will ride a three-game win streak into next Sunday’s game at Detroit. The undefeated Lions (4-0) host the Chicago Bears (2-2) on Monday night.

“We’ll move on with humble hearts and get ready for Detroit,” said coach Jim Harbaugh, whose team was coming off fourth-quarter comeback wins at Cincinnati and Philadelphia.

The 49ers could be moving on for the foreseeable future without starting wide receiver Joshua Morgan. He injured his right ankle making a 19-yard reception at the 1-yard line with 4:20 remaining. CSN Bay Area reported that Morgan suffered a fracture, but a 49ers spokesman would not confirm that.

The 49ers’ offense had an otherwise spectacular showing. Quarterback Alex Smith threw a season-high three touchdown passes to key a 127.2 passer rating, the second-best of his career.

As was the case in the other three wins, Smith had no passes intercepted. He completed 11 of 19 for 170 yards, and he had no fumbles or sacks, a testament to the offensive line’s improved protection.

“The offensive line (took) a lot of criticism the first three weeks of the season, and just continued to work hard and get better,” Smith said. “To do that today versus a 3-1 football team, (they) just absolutely dominated up front.”

The 49ers’ defense dominated, too. It produced three turnovers, and none was bigger than Carlos Rogers’ interception that he returned 31 yards for a touchdown and a 14-3 lead early in the second quarter.

Two plays earlier, Gore had lost a fumble at the Buccaneers’ 11-yard line. Recapturing the momentum — and widening the lead — with Rogers’ play “puts us back in business,” Harbaugh said.

Rogers, who had a third consecutive game with an interception, said: “When you take the life out of an offense like that, it’s big.”

Rookie Chris Culliver recorded his first career interception on the Buccaneers’ ensuing series after Rogers’ touchdown. The 49ers converted that turnover into a touchdown, scored by Gore on a 2-yard run for a 21-3 lead.

Creating a third turnover was safety Dashon Goldson, who crashed into receiver Mike Williams and forced a fumble that Patrick Willis recovered at the Buccaneers 36-yard line late in the third quarter.

That led to Smith’s second touchdown pass to Vernon Davis, this one on a 14-yard fade pass. Davis also caught a 23-yard touchdown pass on the opening series after halftime, breaking Ronde Barber’s tackle at the 5 and eventually receiving a congratulatory head butt from Gore on the 49ers bench.

Smith’s first touchdown pass went for 26 yards to Delanie Walker. It was the first time the 49ers scored in the first quarter this season.

Cue up more history: For the first time in 20 years, the 49ers scored a touchdown on their opening possession of each half.

The 49ers punted only once Sunday and committed only three penalties (for 30 yards). In contrast, the Buccaneers had six punts and were penalized nine times for 96 yards, including an unsportsmanlike conduct penalty on coach Raheem Morris.

“They just ran their game. They did the same stuff — the same passes, the same runs, no different,” Morris said of the 49ers. “They just came out physical and outplayed us. It was a great job by the Niners.”

For more on the 49ers, see Cam Inman’s Hot Read blog at blogs.mercurynews.com/49ers.