Dane Reynolds performs during the first round of the men's competition during the Vans U.S. Open of Surfing on the south side of the Huntington Beach Pier on Monday. (Charles Ryder, HB Independent / July 30, 2014)

The competition has been kicked up several notches and the field of competitors battling for titles has been whittled down at the Vans U.S. Open of Surfing, which reaches its climax this weekend at the Huntington Beach Pier.

The nine-day event, which got under way Saturday, runs daily through Sunday, offering intense competitions in surfing, skateboarding and BMX bike riding.

The U.S. Open of Surfing is an important stop for the Men's Assn. of Surfing Professionals Qualification Series and the Women's World Championship Tour. The ASP Prime event offers valuable points toward a top 10 QS ranking for the men, and the U.S. Open is the halfway point of the World Championship Tour for the women.

Huntington Beach athletes got off to a great start in Round 1 of the U.S. Open Men's Prime at the Surf Stadium.

In the second heat Monday in Round 1 of the main event, Tim Reyes held the lead from start to finish to advance.

Brett Simpson, a two-time U.S. Open men's champion, eased to victory in his opening heat Tuesday.

Reyes and Simpson were among the 48 surfers to reach Round 2. The top two finishers in each Round 1 heat advanced to Round 2.

Results from Round 2 heats weren't available at press time.

Reyes, who was coming off a win at the Prime-rated Mr. Price Pro Ballito in South Africa this month, won his opening heat Monday with a score of 15.14. He finished ahead of Nathan Yeomans (USA, 14.40), Dion Atkinson (Australia, 13.16) and Cooper Chapman (Australia, 11.70).

Simpson led comfortably throughout his heat Tuesday and won with a score of 14.50. He topped Ryan Callinan (Australia, 12.10), Hodei Callazo (Spain, 9.60) and Mitch Coleborn (Australia, 7.60) to move to Round 2.

Simpson was surrounded by autograph seekers and asked to pose for photos once he emerged from the water after winning the 23rd of 24 Round 1 heats.

"These first heats are always tricky, so I'm glad to get this one out of the way," Simpson said. "After the year I've had, I didn't want to think about anything out there (in the water). The conditions here are tough, and I just wanted to take my time.

"I started a bit slow but then reacted to the waves I like to ride, and once I had the lead, it was nice to be able to pace myself. I felt really relaxed throughout the heat."

One thing is certain: There will be a new men's division winner at the U.S. Open this year. Last year's champ, Alejo Muniz of Brazil, finished third behind winner Alex Ribeiro (Brazil) and second-place Dane Reynolds (USA) in his Round 1 heat Monday and didn't advance.

Kanoa Igarashi of Huntington Beach, a wild-card entry in the Men's Prime, scored a Round 1 heat victory Monday against 2012 U.S. Open champion Julian Wilson (Australia), Yadin Nicol (Australia) and Dillon Perillo (USA). The 16-year-old's score of 17.66 (out of 20 possible points) was the highest score of all 24 Round 1 heats.

On the women's side, 2013 U.S. Open champion Carissa Moore of Hawaii won her Round 1 heat Tuesday, the first day of the women's competition, to stay in the running for a repeat title. Other Round 1 heat winners Tuesday were Dimity Stoyle (Australia), Tyler Wright (Australia), Sally Fitzgibbons (Australia), Stephanie Gilmore (Australia) and Lakey Peterson (USA).

Athletes also are contending for titles in the U.S. Open Men's Junior Pro, the Women's Junior Pro and the Vans Joel Tudor Duct Tape Invitational, the latter a featured surf exhibition during the Open.

The women's Round 4, men's Round 3 and men's Junior Pro quarterfinal heats are Thursday. Friday's schedule includes men's Round 4, women's quarterfinal and Joel Tudor Duct Tape Invitational quarterfinal heats. Saturday offers the men's Round 5, Duct Tape Invitational semifinals and finals, and the women's and men's Junior Pro semifinals and finals.

The U.S. Open winds down Sunday with the men's quarterfinals, semifinals and finals and the women's semifinals and finals. The women's final starts at about 12:20 p.m., with the men's final to follow.

Skateboarding and BMX competitions go into full speed this weekend at the concrete Vans Pro Bowl. The Van Doren Invitational prelims and skate qualifiers are Friday. The skate semifinals and finals are Saturday, and the BMX final is Sunday.

Just outside Huntington Surf & Sport on Friday will be the final inductions of the 2014 class in the Surfers' Hall of Fame. Surfer and filmmaker Timmy Turner of Huntington Beach and renowned board shaper and entrepreneur Rusty Preisendorfer will be inducted.

Moore, the other member of this year's class, was inducted Friday.

michael.sciacca@latimes.com

Twitter: @MikeSciacca