It’s taken 30 years, but Dwight Clark finally understands the phenomenon he helped create with the San Francisco 49ers, because he’s experiencing it from the other side this season.

“I guess this is what fans were feeling back in ’81,” Clark said. “When something good happens, it’s almost shocking. Did we really just beat Pittsburgh in Pittsburgh in ’81? Did they really just beat Philadelphia in Philadelphia?

“To me that’s the biggest similarity — the shock value. It’s surprising. And it’s awesome.”

Tuesday is the 30th anniversary of “The Catch,” Clark’s touchdown reception against Dallas that put the 49ers in their first Super Bowl and launched a dynasty. The run of success lasted more than 15 seasons and five Super Bowl victories, before the 49ers fell on hard times.

Now, with the 49ers back in the playoffs for the first time since the 2002 season, hosting the New Orleans Saints in an NFC divisional matchup Saturday, the parallels between this season of rebirth and that season three decades ago are inescapable here.

Tuesday is the 30th anniversary of Dwight Clark’s legendary reception that put the San Francisco 49ers in the Super Bowl and launched their dynasty. (Thearon W. Henderson/GETTY IMAGES)

Jim Harbaugh, the head coach who has orchestrated the turnaround, came to the 49ers from Stanford, like former head coach Bill Walsh. He runs a version of the West Coast offense that Walsh perfected in the early 1980s. And, like Walsh before him, Harbaugh has taken a league laughing stock and turned it into a formidable force.

“Three quarters of the guys on the ’81 team are [angry] at me for saying so, but position by position — and we obviously had some great, great players — all in all, I think this is a better team,” said former team owner Eddie DeBartolo Jr.

The 49ers roster — save for a handful of players such as former Redskins cornerback Carlos Rogers — is virtually the same as it was a year ago, when the team finished 6-10 under Mike Singletary, who was fired with one game remaining in the regular season.

Harbaugh was hired in early January but, because of the NFL lockout, he had virtually no time to work directly with his players. Expectations were decidedly low.

“I just wanted Harbaugh to get people talking about the 49ers again,” Clark said. “Nationally, no one paid any attention to us. I was just hoping he could jump-start things a little.”

Harbaugh’s debut as head coach came in a preseason game in New Orleans. His team looked every bit like the inept group that had struggled in previous seasons. The 49ers lost, 24-3, the offensive line was overwhelmed by the Saints’ relentless blitzes, quarterback Alex Smith struggled and it seemed obvious it would take Harbaugh at least a full season to execute a turnaround.

Five months later, the 49ers have a 13-3 record and secured the second seed in the NFC, nudging out the Saints in a tiebreaker.

“We’re not even the same team as that preseason game,” said tackle Joe Staley. “We have so much more confidence, we’re so much more sure of ourselves and the schemes and what we’re doing.”

As they were in 1981 when they took on Danny White and “America’s team,” the 49ers are likely to be overshadowed by Drew Brees and the record-setting Saints offense. The Saints are favored by 31 / 2 points despite being on the road.

That’s fine with the 49ers. Harbaugh has fostered an underdog mentality in his team. Early in the season, he noted how infrequently the 49ers were shown on Sunday night highlights. But as the 49ers kept winning, Harbaugh’s task of playing the underdog has become more difficult.

He still can assume his offense is disrespected. Despite DeBartolo’s claims about the superiority of this team, the 49ers lack the glamour passing offense that the 1981 team had in a young Joe Montana, Clark and Freddie Solomon. Smith — who has suffered a career’s worth of abuse in his first six years in the league — has proved to be a winning quarterback, but the 49ers rank 29th in passing offense. This team is built around the run: Frank Gore is the fifth-ranked rusher in the league.

The 49ers’ best hope will be to control the ball and play for field position, limiting Brees’s chances. When the Saints — with the league’s second-ranked offense — do take the field, they will face the 49ers’ second-ranked defense.

The 1981 49ers’ defense also was ranked second in the league. And despite Montana’s off-balance throw and Clark’s leaping, dazzling catch, it was defense that ultimately won the NFC championship game.

“I was so caught up in the moment,” Clark said. “And the next thing I know they were at midfield. I thought, ‘No way, are they going to do this to us again.’ ”

With 51 seconds left, the Cowboys, down 28-27, got the ball back and were driving into field goal range. Rookie cornerback Eric Wright made a game-saving tackle on Drew Pearson. Lawrence Pillers then stripped the ball from White and his defensive linemate, Jim Stuckey, recovered it. Candlestick Park erupted.

Saturday’s game will be hosted at the same decrepit venue — a decided advantage for the 49ers over New Orleans’s Superdome, where the Saints were 8-0 this year.

In recent years the 49ers have been working to build a new stadium in Santa Clara. But fans believe there’s at least one more moment of glory left in the stadium that DeBartolo once described as “a pigsty.”

“You can’t dress it up,” said Clark, who will be there Saturday hoping, three decades later, that the old park is still capable of hosting another surprise.