American Ken Read, the 'old man' of the Volvo Ocean Race at 50, gave some of the fleet's younger skippers a tactical master class to throw the event wide open.
Spain's Team Telefonica had swept all before them in winning the first three stages to take a big lead ahead of the 5,220-nautical mile fourth leg from southern China to Auckland.
However, victory late on Saturday for French challengers Groupama, despite a gash in their hull that leaked over a tonne of water, had shown that Iker Martinez's crew were not invincible and Read in Puma underlined the point some 12 hours later in taking second place from them.
The experienced campaigner from Rhode Island took a huge tactical gamble mid-leg when he sailed north away from the rest of the fleet, directly away from Auckland and towards Japan.
Read knew exactly what he was doing, free-wheeling on the stronger winds and by-passing all but Groupama in the sprint in to Auckland in sometimes brutal conditions with waves of up to eight metres.
"My God, I feel good to be in Auckland," Read said immediately after the finish.
"From day one of this leg, ever since we sailed into the South China Sea, it's been tough. I know that's what we signed up for but, man, this is a challenging leg."
Telefonica only just held on to third, edging out Team New Zealand's Camper by 1min 33sec after more than 20 days of sailing. Abu Dhabi held China's Team Sanya at bay to claim fifth.
The results left Telefonica just 18 points clear with Groupama leapfrogging Camper into second spot overall.
The event resumes next Saturday for the Auckland in-port race with the next leg to Itajai, Brazil beginning the following day. The 39,000-nautical mile, nine-month race finishes in Galway, on 8 July.
Overall standings after four legs: 1 Team Telefonica (Spain) 121 pts, 2 Groupama (France) 103, 3 Camper (Spain/New Zealand) 98, 4 Puma (US) 78, 5 Abu Dhabi 53, 6 Team Sanya (China) 22.