SAN FRANCISCO -- An NFL head coach lost his cool Sunday, drawing a penalty for unsportsmanlike conduct during a mistake-filled defeat marked by poor play from a highly drafted quarterback.

The San Francisco 49ers lived this nightmare too frequently when fire-breathing Mike Singletary was their coach and the old Alex Smith was their quarterback.

No longer.

The visiting Tampa Bay Buccaneers played the fools Sunday. Their across-the-board incompetence was no match for the cool precision San Francisco projected during a 48-3 victory that validated the two-game road sweep preceding it.

The penalty Bucs coach Raheem Morris drew while berating officials recalled the sideline fury Singletary regularly demonstrated in shouting down his quarterbacks and, once, getting into an in-game argument with an opposing player. On the field Sunday, the poor decisions Tampa Bay quarterback Josh Freeman made could have been pulled directly from a pre-Harbaugh 49ers script.

Only one game? Perhaps for the Bucs, who were traveling across the country on a short week, with a home game against division-rival New Orleans awaiting them in Week 6.

It's tougher to dismiss this outcome for the 49ers. They're 4-1 and winning with the right mix of offense, defense and special teams. They've won three in a row for the first time since 2006, with two of those victories in the Eastern time zone. They've gotten to plus-10 in turnover differential by playing smarter and more opportunistically than their opponents, not through gambling or luck.

Call it the Harbaugh effect.

"You act like your coaches," said 49ers tight end Delanie Walker, whose 26-yard scoring reception got the 49ers rolling. "We are going to keep our heads, keep our cool and make smart decisions. When other teams make bad decisions, we capitalize on that."

It's tough to overstate the differences between Harbaugh's 49ers and their 2010 predecessors.

Last season, the Singletary-coached 49ers suffered a 21-0 home defeat to Tampa Bay, their first shutout at Candlestick since 1977. The 48-3 score Sunday represented a 66-point swing.

Last season, the 49ers took an 0-5 record into a game against Oakland that carried only local appeal. This season, they're four games better in the standings and headed to Detroit for one of the NFL's more intriguing matchups of Week 6.

Whereas Singletary was all about the big picture -- motivating players and leaving the details to his staff -- Harbaugh thirsts to know every aspect of the 49ers' operation.

"Everyone is just very, very detailed in what they are doing," left tackle Joe Staley said. "It's the receiver knowing they're not going to get the ball, but running that route 400 percent speed so he can clear out the safety. It's about getting different adjustment calls at the line of scrimmage without having to say more than one word, and everyone knowing what their responsibilities are."

How detailed is Harbaugh? Let us count a few of the ways:

Practice management: Harbaugh manages practice time periods himself instead of using the large on-field clocks conventional in the NFL, the better to control the pace of how the 49ers operate.

Game-day operations. In years past, 49ers coaches relied upon team executive Paraag Marathe to oversee the decision-making process for instant replay. Harbaugh has his coaches handling that aspect from the booth.

Meeting immersion: Harbaugh isn't the first head coach to spend time in meetings outside his primary area of expertise, but he takes it to the extreme -- including attendance at the 8:45 a.m. special-teams meetings Tuesday through Saturday.

Player interaction: Harbaugh regularly leaves the practice field with players from varied position groups, seeking a first-hand feel for the locker room. He gives up his first-class seat on the team plane, preferring instead to sit with players.

Pronunciation guide: Harbaugh took time during his postgame news conference to rather emphatically correct a reporter's pronunciation of nose tackle Ricky Jean-Francois' name. A bit abrasive of the head coach? Sure, but he couldn't let it slide.

On-field results suggest players have bought in fully.

Against the Bucs, we saw alleged diva receiver Michael Crabtree blocking multiple defenders on the same play, freeing teammate Josh Morgan for a 24-yard gain. We saw receiver Ted Ginn Jr., a football player with a track man's body, blocking Aqib Talib aggressively enough to send the Bucs' cornerback flying toward the 49ers' bench.

"I love the fact that he [Harbaugh] motivates us and has us ready to win every game," Crabtree said.

As Singletary's tenure proved, motivational tactics carry short shelf lives unless coaches demonstrate over time they have scheme-related answers for their team's troubles.

The 49ers had all the answers Sunday. They amassed a 418-272 advantage in total yards while doubling up Tampa Bay in first downs, 28-14. Their secondary in particular played with confidence, picking off Freeman twice. Carlos Rogers' 31-yard interception return for a touchdown turned a 7-3 game into a budding rout.

Most importantly, Harbaugh's ability to coax generally consistent, mistake-free play from Smith stands as his greatest achievement so far. Smith had six touchdown passes with nine interceptions at this point last season. With three scoring passes Sunday, the ratio stands at 7-1 through five games. Smith said there are no secrets, only an unrelenting staff-driven focus on the smallest details.

Smith attempted only 19 passes Sunday, completing 11 for 170 yards. He took no sacks, tossed three scoring passes to his tight ends (one to Walker, two to Vernon Davis) and managed the game superbly. He finished the game with a 127.2 NFL passer rating and, according to Hank Gargiulo of ESPN Stats & Information, a 98.2 out of 100 in Total QBR.

Smith has passed for 15 touchdowns with only two interceptions over his last 10 starts, winning seven of them. That suggests some of his growth predates the arrival of Harbaugh and offensive coordinator Greg Roman.

"I feel good about where I'm at," Smith said.

A year ago Monday, Singletary famously moved to bench Smith following a disastrous sequence during a nationally-televised game against Philadelphia. Singletary relented after Davis rallied to his quarterback's defense.

Against Tampa Bay, the 49ers sent Smith to the bench for nearly all of the fourth quarter -- not as punishment, but as a reward for leading the most lopsided 49ers victory since 1987.

It's the Harbaugh effect. What else could it be?