That also makes the defending NFC champions the type of team the improving Buccaneers need to knock off to prove their second-half turnaround isn't a fluke.
Not that star cornerback Darrelle Revis and his teammates necessarily believe the Bucs (4-9), who've won four of five following an 0-8 start, need a signature win to validate their progress.
"It would be special if we win because they're one of the top teams in the NFL. But at the same time, a win is a win," the three-time All-Pro said.
The streaking 49ers (9-4) are coming off an emotional 19-17 victory over Seattle, a win that stopped the Seahawks from clinching the NFC West title.
Three teams Tampa Bay has beaten had losing records at the time. The fourth, Detroit, leads its division but has been reeling lately and is 7-6.
Linebacker Patrick Willis is not concerned about a Niners letdown.
"We understand every game is important to us. We understand that last week was a very big game, a rivalry game, but this week is just as important," Willis said.
"Our guys are professionals, they know what's at stake," 49ers coach Jim Harbaugh said.
"This game is the biggest game on the schedule. This is a must-win game ... by any means necessary. The first thing is the preparation. You've got to put yourself in a position to earn that. And, our guys will be committed and professional about doing that."
Five things to watch as the 49ers seek their fourth straight win and the Bucs try to build on their recent success:
DEFENDING DAVIS: While Anquan Boldin is drawing plenty of attention in the 49ers' passing game, Vernon Davis is showing each week why he is such a factor in San Francisco's success. The Bucs might want to watch out for Davis' high-hurdling move, too.
San Francisco's speedy tight end has a touchdown catch in each of the past four games, the third time in his career he's done so. Davis has 11 TD receptions on the season.
With Boldin — he has at least five catches in each of the past four games — and Michael Crabtree forcing defenders to stay with them, Davis might not see many double-teams.
Crabtree has played two games since returning from six months recovering from a torn right Achilles tendon.
"That's a valid point," Harbaugh said. "There's been times throughout the year where Anquan's gotten doubled and Vernon's gotten doubled on the same play. Michael's presence out there and everything he's done and everything he's shown he can do since coming back, that's another guy, high-level guy, that's got to be accounted for."
GLENNON'S PROGRESS: Bucs rookie quarterback Mike Glennon has struggled his past two starts, throwing three interceptions and losing a fumble. Last week, Tampa Bay forced five turnovers during a rout of Buffalo, but the sputtering Bucs offense produced only two field goals off the miscues.
STOPPING GORE: Tampa Bay's first priority is to stop the run. The 49ers are sixth in the NFL in rushing, and Frank Gore is within 69 yards of reaching 1,000 for the seventh time.
"I'll openly say it: Frank Gore is our focal point," McCoy said. "If you can slow that guy down then we can start worrying about everything else."
FAST STARTERS/SLOW FINISHERS: The 49ers have outscored opponents 181-93 in the first half. The Bucs, who hold a 174-145 edge in the opening half, have been outscored 146-70 after halftime.
FRIENDS OR FOES? 49ers right tackle Anthony Davis doesn't sound like he will go out of his way to offer a pregame greeting to his former Rutgers coach, now Bucs head coach Greg Schiano.
"I don't know," Davis said. "If we make eye contact, I'll acknowledge him out of respect."
They had their moments during his college playing days, when Davis was disciplined more than once for team rules infractions by the intense, fiery coach. In fact, Davis referenced a quote from Schiano after receiving a five-year extension in April worth more than $37 million, with $17 million guaranteed.
The O-lineman posted: "You will be a 1 contract and done kinda guy in the NFL. - Greg Schiano. Lol"
Schiano credits Davis for continued improvements and hopes he pushed the right buttons to help Davis succeed.
"I had coached in the NFL and I told him stories about guys that can either go be long-term NFL players and get their second and third contract, or they can be fizzle-out guys," Schiano said. "And I just wanted to make sure Anthony — you know, he was talented enough to get second, third and fourth contracts, really. He's that good an athlete. And he's well on his way now."