Taylor appeared to make his decisive move in the ski leg, before Beattie summoned one last burst to draw level heading into the beach.
"I didn't know if it was Max or Tanyn coming for me at the end but then I saw the yellow tip of Max's ski edge into view and just thought, 'Here we go again,'" Midway's Taylor said. "I'm obviously a bit disappointed but I was happy with how the race went."
Another Australian, Kristyl Smith, won the ironwoman final, after a strong swim leg took her out in front of Kiwis Devon Halligan and Danielle McKenzie.
Halligan claimed the New Zealand title ahead of McKenzie, although Smith was wary of a quality field: "The competition has been awesome and I've really had to put my head down in each race," she said. "Natalie Peat is on fire, Devon's going great and Danielle McKenzie is the best board paddler in the world at the moment, while I've had a couple of really close battles with Devon over the years, so it was great to come out on top."
Halligan won the board race, outsprinting Smith and McKenzie, while Papamoa's Peat won the surf race.
The undoubted female star of the carnival, however, was one of the youngest athletes competing. Midway's Olivia Corrin, at just 14, walked away with 10 gold medals from the three days, including a gold in the open board relay and a bronze in the open board rescue with Halligan.
Beattie also claimed the board race title, while Titahi Bay kayaker Marty McDowell collected his fourth open men's ski title, pulling away from Mairangi Bay pair Kevin Morrison and Travis Mitchell.
"I tried for a long time to win this race and it took a while but now I've got a taste for it - I'm really looking forward to getting back and having another go next year," McDowell said.
Arch-rivals Piha and Titahi Bay shared the spoils in the open men's surf boat arena, although Titahi Bay ended a five-year drought by winning the feature long-course final, ending Piha's four-year domination.
Mt Maunganui finished on 213 points, more than double the total of second-placed Midway (104), with Mairangi Bay third on 70.