Anticipation is building for Sunday's season finale of "The Sopranos" (search) — and HBO is hoping for a knockout ratings punch.

There's good reason to believe that will happen: The show's fourth-season finale, which aired in December 2002, snared 12.5 million viewers, huge numbers for a cable show.

Even more remarkably, the 2002 season finale beat the competition on the broadcast networks — which almost never happens.

"I think [Sunday's finale] is going to do well, but I don't think it will be a record high," says industry analyst Marc Berman of Mediaweek. "HBO stakes a lot on this [season finale], and it's extremely critical to them.

"They lost 'Sex and the City,' (search) and 'Six Feet Under' has never been a huge hit like 'The Sopranos,' " he says. "But Sunday's finale will certainly be above the show's season average, probably closer to 13 million viewers."

"The Sopranos" is averaging 9.7 million viewers this season through 12 episodes — down 10 percent from last season's average (11 million viewers).

Over the last few weeks, series creator David Chase (search) has worked some jolting plot developments into the show — including the whacking of Adrianna, and having James Gandolfini's Tony (tenuously) reconcile with wife Carmella.