Universal's spy thriller The Bourne Ultimatum roared to the top of the North American charts on the back of wildly enthusiastic reviews and set a record estimated $70.2m August launch in the process.

The third and supposedly final episode in the saga of the amnesiac covert operative scored the biggest opening in the franchise, following the $27.1m launch of The Bourne Identity in June 200 and $52.5m for The Bourne Supremacy in July 2004.

Matt Damon stars alongside Julia Stiles, Joan Allen, David Strathairn and Paddy Considine. Paul Greengrass directed, as he did on the second episode.

Bourne's heroics relegated The Simpsons Movie to second place, however the comedy is still keeping a smile on the faces of audiences and 20th Century Fox executives alike and added $25.6m for a $128.6m tally after two weekends.

Buena Vista's children's television adaptation Underdog, about a superhero pet, opened third on $12m. Jason Lee voices the caped canine, while Peter Dinklage and James Belushi also star.

Universal's former table topper I Now Pronounce You Chuck And Larry is nearing $100m and ranks fourth on $91.7m after three weekends, and New Line's musical Hairspray continues to perform well as one of the summer's more accomplished counter-programmers in fifth place on $78.9m after three.

Warner Bros' Harry Potter And The Order Of The Phoenix ranks sixth on $260.8m after four, and DreamWorks/Paramount's Transformers stands at the cusp of $300m in eighth place and has amassed $296.3m after five.

Saturday Night Live regular Andy Samberg's feature acting debut didn't get off to a good start as Paramount's comedy Hot Rod opened in ninth place on $5m, while Lionsgate's high school feature Bratz, based on the doll line, launched to dismal reviews in 10th place on a disappointing $4.3m.

Next weekend's wide releases are: New Line's buddy movie sequel Rush Hour 3 with Jackie Chan and Chris Tucker; Paramount's fantasy adventure Stardust with Claire Danes, Michelle Pfeiffer and Robert De Niro; Sony's comedy Daddy Day Camp starring Cuba Gooding Jr; and the wide expansion of Miramax's drama Becoming Jane with Anne Hathaway and James McAvoy.

Estimated Top 10 North America Aug 3-5, 2007
Film (Dist)/Int'l dist/Est wkd gross/Est total to date
1 (-) The Bourne Ultimatum (Universal) UPI $70.2m -
2 (1) The Simpsons Movie (Fox) Fox International $25.6m $128.6m
3 (-) Underdog (Buena Vista) WDMPI $12m -
4 (2) I Now Pronounce You Chuck And Larry (Universal) UPI $10.5m $91.7m
5 (4) Hairspray (New Line) NLI $9.3m $78.9m
6 (3) Harry Potter And The Order Of The Phoenix (Warner Bros) WBPI $9.3m $260.8m
7 (5) No Reservations (Warner Bros/Village Roadshow) WBPI $6.6m $24.2m
8 (6) Transformers (Paramount) PPI $5.9m $296.3m
9 (-) Hot Rod (Paramount) PPI $5m -
10 (-) Bratz (Lionsgate) $4.3m -