NORTH AMERICA: Studio Estimates: 'Guardians of the Galaxy' Leads with $17.6M; 'If I Stay' #3 with Solid $16.4M; 'When the Game Stands Tall' #5 with Modest $9.0M; 'Sin City' Sequel Tanks with $6.5M

Sunday Update: Disney's Guardians of the Galaxy claimed first place this weekend with an estimated $17.63 million. The blockbuster sci-fi superhero adaptation from Marvel returned to first place after finishing in second each of the past two weekends. Guardians of the Galaxy held up extremely well this weekend, as it was down just 30 percent from last weekend. Guardians of the Galaxy surpassed the $250 million mark this weekend and has grossed $251.88 million in 24 days. That currently ranks the film as the third highest grossing release of 2014 thus far domestically (behind only Captain America: The Winter Soldier and The Lego Movie). Guardians of the Galaxy is set to move into first place for the year within the next week.

After leading the box office each of the past two weekends, Teenage Mutant Ninja Turtles fell to second with an estimated $16.8 million. Paramount's successful franchise re-launch was down a solid 41 percent from last weekend. Teenage Mutant Ninja Turtles continues to exceed expectations in a big way with $145.61 million through 17 days of release. The film will zoom past the $150 million domestic mark within the next week and should continue to further stabilize next weekend with help from the Labor Day holiday.

Warner's If I Stay debuted in third with an estimated $16.36 million. The low-budget drama starring Chloë Grace Moretz opened towards the lower end of pre-release expectations and performed well with its cost in mind. If I Stay opened slightly ahead of the $16.10 million debut of last year's Carrie, which also starred Moretz. Due in part to its different genre and in part to the limited amount of new wide releases over the next few weeks, If I Stay will hope to hold up better going forward than Carrie did. If I Stay opened with $6.82 million on Friday (which included an estimated $1.1 million from late night shows on Thursday), fell 18 percent on Saturday to take in $5.61 million and is estimated to fall 30 percent on Sunday to gross $3.93 million. That places the film's estimated opening weekend to Friday ratio at 2.40 to 1. The audience breakdown for the film skewed heavily towards female moviegoers (77 percent) and moviegoers under the age of 25 (61 percent). If I Stay received an encouraging A- rating on CinemaScore.

Let's Be Cops followed in fourth with an estimated $11.0 million. Fox's low-budget action-comedy held up well in its second weekend, as it was down 38 percent from last weekend. Let's Be Cops has grossed $45.25 million in twelve days. That is in line with the lower end of expectations and places the film 21 percent behind the recent $56.99 million twelve-day take of Tammy. Let's Be Cops will likely continue to hold up well going forward thanks in part to no new comedies entering the marketplace the next few weeks.

Sony's When the Game Stands Tall rounded out the weekend's top five with an estimated $9.0 million. The low-budget drama from TriStar and AFFIRM Films opened on the low end of expectations. When the Game Stands Tall opened just below the $9.78 million start of Draft Day earlier this year. The film opened with $3.00 million on Friday, increased 20 percent on Saturday to gross $3.60 million and is estimated to decline 33 percent on Sunday to gross $2.40 million. That gives the film an estimated opening weekend to Friday ratio of 3.00 to 1.  When the Game Stands Tall received a promising A- rating on CinemaScore and will have a good chance of holding up well going forward.

Meanwhile, fellow new release Sin City: A Dame to Kill For absolutely stumbled out the gate this weekend with an extremely disappointing estimated eighth place start of just $6.48 million. The graphic novel adaptation sequel opened well below all expectations and a massive 78 percent below the $29.12 million start of 2005's Sin City (which didn't the advantage of higher priced 3D admissions). Unlike 300: Rise of an Empire earlier this year, Sin City: A Dame to Kill For was unable to overcome the long gap in time between it and its predecessor. The film opened with $2.62 million on Friday, fell 18 percent on Saturday to take in $2.14 million and is estimated to decline 20 percent on Sunday to gross $1.71 million. That places the film's estimated opening weekend to Friday ratio at 2.47 to 1. Sin City: A Dame to Kill For received a lackluster B- rating on CinemaScore.

The Giver and The Expendables 3 claimed sixth and seventh place with respective estimated takes of $6.73 million and $6.6 million. The Weinstein Company's The Giver was down a reasonable 45 percent from last weekend, while The Expendables 3 fell a sharp 58 percent. Respective ten-day totals stand at a solid $24.10 million for The Giver and at a very disappointing $27.52 million for The Expendables 3.

Saturday Update: Warner Bros. reports that If I Stay grabbed $6.83 million on Friday, including Thursday's $1.1 million sneaks. That's a healthy start for the young adult adaptation and sets it up nicely for a weekend around $17 million. If I Stay's opening day was 44 percent higher than The Giver's last week, and just 12 percent behind August 2009's The Time Traveler's Wife. The film's CinemaScore was a solid "A-", while Flixster users are more middling at 75 percent.

The race for first place could be a close one, though. Disney/Marvel's Guardians of the Galaxy slipped just 30 percent from last Friday to $4.83 million yesterday, taking second place. The flick boasts $239.1 million in the domestic bank so far, and it will overtake Transformers: Age of Extinction on Saturday to become the summer's highest grossing film. The pic is also an impressive 12 percent ahead of the pace of Captain America: The Winter Soldier. BoxOffice projects a $17.2 million return to first place for Guardians' fourth weekend.

Teenage Mutant Ninja Turtles was no slouch itself on its third Friday, dropping a healthy 43 percent from last Friday to $4.54 million. The reboot has claimed $133.35 million to date, 19 percent ahead of the pace of G.I. Joe: The Rise of Cobra. BoxOffice projects $16.1 million for its third frame.

When the Game Stands Tall earned $3 million yesterday, 44 percent behind the opening day take of 2006's Invincible. BoxOffice projects a $9.5 million opening weekend.

Meanwhile, Sin City: A Dame to Kill For was dead on arrival Friday. The nine-years-in-the-making sequel took in $2.62 million on Friday after an already disappointing $480,000 Thursday night start. The opening day figure is 55 percent lower than last year's Kick-Ass 2, and puts the film on course for an opening frame around $6 million. For reference, the original Sin City took in $11.8 million on opening day alone in its April 2005 debut. Early fan word of mouth appears mixed with a 76 percent Flixster score, comparable to 300: Rise of an Empire's 73 percent one day after release.

Friday Update #2: Sources tell BoxOffice that If I Stay is pacing for an opening day around $5 million. If that holds, an opening weekend in the $13-14 million range is likely.

Meanwhile, When the Game Stands Tall is performing on par with expectations around a $3.5 million Friday. That would likely get the film over $10 million for the weekend.

The news isn't improving for Sin City: A Dame to Kill For. After alarmingly low Thursday night numbers, sources report that the sequel may net around $4 million today. If that holds, a sub-$10 million weekend remains very likely (possibly closer to $9 million).

Friday Report #1: Warner Bros. reports that If I Stay bowed to a healthy $1.1 million gross from Thursday shows starting at 7pm. Previously, Fandango reported the adaptation was leading all films in pre-weekend ticket sales in what's shaping up to be a chase for first place.

Appropriate comparisons would seem to be The Fault In Our Stars ($8.2 million Thursday opening) and Divergent ($4.9 million), however, those films were more likely to be front-loaded given their dedicated fan base and pre-release hype. A fair comparison may be that of the Carrie remake, also starring Chloe Grace Moretz, which opened to $0.73 million on Thursday as part of its $16.1 million opening weekend. Additionally, last week's The Giver earned $0.75 million as part of a $12.3 million frame.

Meanwhile, Sin City: A Dame to Kill For opened soft last night with $0.48 million. The nine-year wait for the sequel undoubtedly tempered excitement outside the fanboy crowd. By comparison, last August's Kick-Ass 2 pulled $1.3 million from Thursday 8pm shows and went on to a disappointing $13.3 million weekend. A sub-$10 million weekend for the Sin City sequel looks likely.

When the Game Stands Tall earned $0.425 million last night, slightly more than Draft Day's $0.31 million earlier this year. The film could end up around $10 million this weekend.