Enlarge By Mark Fellman, 20th Century Fox Avatar, with Sam Worthington as Jake Sully, was No. 1 for a fourth consecutive week at the box office. TOP 10 FILMS OF ALL TIME TOP 10 FILMS OF ALL TIME Titanic

1997 | $601 million The Dark Knight

2008 | $533 million Star Wars

1977 | $461 million Shrek 2

2004 | $441 million E.T.: The Extra-Terrestrial

1982 | $435 million Star Wars: Phantom Menace

1999 | $431 million Avatar

2009 | $429 million Pirates of the Caribbean:

Dead Man's Chest

2006 | $423 million Spider-Man

2002 | $403 million Transformers: Revenge

of the Fallen

2009 | $402 million Note: Star Wars and E.T. made lifetime

gross over multiple releases. Source: Boxofficemojo.com

Director James Cameron is bearing down on his own legacy.

Cameron's sci-fi opus Avatar claimed the No. 1 spot at the box office for the fourth straight weekend and continues to demolish records, including the filmmaker's own.

Avatar raked in $48.5 million, according to studio estimates from box-office tracking firm Nielsen EDI.

TOP 10 CHART: See how your favorite films fared at the multiplex

The haul brings Avatar's total to $429 million and was enough to make the 3-D spectacle the biggest movie of 2009. It beat out Transformers 2: Revenge of the Fallen, which made $402 million.

Avatar shattered the record for highest fourth-weekend ticket sales. The previous titleholder: Cameron's Titanic, which earned $28.7 million in 1997.

The weekend haul also moved Avatar to seventh on the all-time list of biggest films. The strong hold — the movie dropped just 29% from last weekend — means it could be in striking distance of The Dark Knight, which is the second-biggest film with $533 million.

That would leave it chasing Titanic's most prized title: highest-grossing film of all-time at $601 million.

Though 20th Century Fox executives were careful not to draw comparisons between Cameron's films, it's clear they were enjoying the race.

"Avatar became water-cooler talk," says Fox's Bert Livingston. "People are seeing it so they can be part of the discussion. I think people who haven't seen it yet are becoming the minority. Who knows how high this thing can go?"

The film is helping business at all turnstiles. Ticket sales were up 18% over the same weekend last year, getting 2010 off to a quick start.

Robert Downey Jr.'s Sherlock Holmes was second with $16.6 million, which brings its total to $165.2 million.

Alvin and the Chipmunks: The Squeakquel continues to be a quiet powerhouse. It brought in $16.3 million, good for third place and an overall gross of $178.2 million.

The horror film Daybreakersfell slightly below expectations with $15 million, and Meryl Streep's It's Complicated rounded out the top five with $11 million in its third week.

The Amy Adams romantic comedy Leap Year had a solid if unspectacular $9.2 million debut. Michael Cera's comedy Youth in Revolt met its modest expectations with $7 million.

Final figures are due today.