LOS ANGELES (Reuters) - The four-day Martin Luther King Day weekend features a box office smackdown between Avatar and the tag-team pairing of two new pictures. If James Camerons behemoth manages to beat the newcomers, it would be the first to top the rankings for five consecutive weeks since The Sixth Sense in 1999. It will also keep tongues wagging over its prospects for cruising past Camerons Titanic in the history books. But the competition appears potentially muscular: Warner Bros. sends out the Denzel Washington action movie The Book of Eli, and Lionsgate launches the Jackie Chan comedy The Spy Next Door, a more family-friendly action film. Last weekend, Avatar shrugged off a trio of wide openers in posting the first four-peat performance since The Dark Knight in the summer of 2008. Meanwhile, theres talk of Fox setting Avatar for DVD release in April. But dont expect an official decision until Avatar starts running out of theatrical steam, and nobody anticipates that happening anytime soon. In fact, industry observers now say its not impossible for Avatar to beat the $1.84 billion worldwide total for Camerons Titanic. Its North American tally through Wednesday stood at $446 million, behind only Titanic ($601 million), The Dark Knight ($533 million) and Star Wars ($461 million). The sci-fi epic could fall 25%-30% this session it slid 27% last weekend and still ring up about $36 million, and Monday grosses could take the haul past $40 million. That likely would be enough to beat the newcomers. Eli, skewing significantly male, could fetch $30 million-$40 million through Monday. It marks directing duo Allen and Albert Hughes first theatrical feature since 2001s From Hell. Washingtons movies usually open in the $20 million range, with the notable exception of 2007s American Gangster, which kicked off with $43 million. Spy looks likely to reach the high-teen millions through Monday. Directed by Brian Levant (Are We There Yet?), the film co-stars George Lopez and Billy Ray Cyrus, both good draws for family moviegoers. Chan was last on screen with 2008s The Forbidden KIngdom, alongside Jet Li. The superstar pairing opened to $21 million. Elsewhere, Peter Jacksons The Lovely Bones opens nationally after a month of limited engagements. The supernatural crime saga should play decently with young women.