“You go over that bridge and it’s like leaving a city and entering a tropical paradise,” as tournament founder Butch Buchholz, the former pro, puts it. “It had that postcard feeling I was hoping for.”

It was a natural.

Tennis fans needed no other excuse but to integrate the tournament in their travel plans, and for players, too, the stop became a busman’s holiday — a place they would visit anyway, even if it didn’t offer a combined men’s and women’s prize purse of $10.4 million this year, a record.

Back in the mid-’80s the event was coined “the winter Wimbledon,” a phrase the promoter Buchholz embraced and encouraged. It has since come to be nicknamed tennis’ “fifth major,” because that is its stature and lure.

(Only that stature and lure make the absence of Federer and Nadal newsworthy … because it seems no one wants to miss Key Biscayne).

The men’s Association of Tennis Professionals tour has voted this its tournament of the year six times, and the Women’s Tennis Association tour has given it that honor twice. The WTA calls Key Biscayne “the largest tennis event in the world outside the four Grand Slams.”

The manicured grounds bounced back from Hurricane Andrew (“We’ve got nine lives,” Buchholz said then) and blossomed to its present 30 acres, that distinctive purple stadium court at the literal and figurative center of it all.

On that stage, annual greatness should be expected.

Men’s champions here have included Ivan Lendl, Agassi, Pete Sampras, Andy Roddick, Murray and Djokovic. Women’s winners have included Martina Navratilova and Chris Evert (those first two years), Graf, Monica Seles, Martina Hingis and Kim Clijsters — oh, and the ubiquitous Williams sisters, of course.

The No. 1 seeds offer quite a contrast, except in excellence. Djokovic, the 25-year-old Serb, has won five of the past nine majors and seems to be just coming into his prime. Serena, 31, won her first Grand Slam event in 1999 and her 14th and 15th last year. Her prime seems remarkably to go on and on and on.

“Can’t wait to hit the purple court for my opening match,” Serena Tweeted this past weekend. “Love Miami in March.”

By Miami she means that little gem of an island 11 miles to the southeast — the paradise capital of tennis for the next two weeks.