Temperatures at the Brisbane Global Tens didn't reach the same unbearable levels as last year's maiden event but early evidence suggests a New Zealand team will again clinch the title.

Rolling subs were in full swing as players battled 33 degree afternoon heat, clambering for cooling fans and wet towels as they trudged from the field, until evening shade brought some welcome respite.

Blues coach Tana Umaga, following his side's impressive first up 29-7 victory over the Reds in which wing Melani Nanai starred with two tries, was happy to take his place on the sideline.

"I don't envy these guys running out there in this heat," Umaga said. "It's amazing when they put themselves through."

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In the first Kiwi derby of the tournament, the Chiefs and Highlanders played out the match of the day.

The Highlanders, wearing high vis jerseys resembling road workers, looked to have stolen victory at the death.

But in a contentious decision, Tevita Nabura's second try in the corner was eventually ruled out, despite being originally awarded, allowing the Chiefs to start the defence of their title with a 17-12 win.

Should Tim Nanai-Williams continue his magic early touches, the Chiefs should be well in contention.

In their first match the Crusaders, last year's beaten finalists, thrashed the Hurricanes 22-0 in a clinical performance.

The Crusaders scored two tries while Jackson Garden-Bachop was in the bin for an attempted intercept, and never looked like being run down. The Super Rugby champions led 17-0 at the break and kicked away for a comfortable win.

With firepower in the form of Jone Macilai and George Bridge complementing drive over tries, the Crusaders boast weapons capable of taking them all the way.

Fielding an experienced team led by Julian Savea, the Hurricanes consistently made errors and never really fired a shot. It was a disjointed, bumbling team effort.

Of the other contenders, the Waratahs and Henry Speight's Brumbies, who took down Fiji 17-12 in a tight tussle, appear the best of Australian teams.

Robbie Deans' Panasonic Wild Knights, just as they did in year one, again showed spirit to comeback from 17 points down to roll the Rebels, 19-17.

The presence of seven former All Blacks failed to inspire Pau, who may still be suffering climate shock with snow back home. Despite Conrad Smith's best efforts, the French club were flogged 31-10 in their opening match by the Waratahs.

Organisers will be hopeful more than day one's 10,000 to 15,000 turn up for the finals.