The understrength NSW Waratahs conceded seven tries in a 55-21 Super Rugby Pacific thumping by the Blues at a wet Eden Park in Auckland.

But the Waratahs hope Saturday's outcome is the worst of it, expecting their cavalry to return and with it some momentum in a six-week run into the finals.

Travelling without the rested Michael Hooper and boasting a bevy of fresh-faced talent, the Waratahs did well to turn away the Blues' many early attacks.

When Waratahs hooker Mahe Vailanu found the line from the back of a rolling maul it was 13-7 and the visitors had designs on just a second win at the venue.

But that same man was sin-binned soon after for a ruck infringement on his try-line, with Blues reserve fullback Zarn Sullivan scoring tries either side of halftime while he was off to break the game open.

Heavy rain then arrived and the Blues slid clear.

A double to hooker Ricky Riccitelli increased the gap and winger Caleb Clarke scored a deserved try after terrorising the Waratahs' defence down the left edge.

The bonus-point victory improved last year's grand finalists to 5-3 as they chase the top four, while the Waratahs (2-6) cling to eighth.

"It's not great for the organisation, having 50 put on you, but sometimes you've got to lose a battle to win a war," coach Darren Coleman told Stan Sport.

Coleman said all of the side's Wallabies squad members had taken their required rest and many others were soon to return from injury for a run home that includes four home games.

"We can get an unimpeded run at the last six (games), get ourselves into some form and in a good position for the play-offs," he said.

Winger Dylan Pietsch was one of the Waratahs' best and managed a try to show for it, running onto an inside ball and then pinning his ears back to make it 41-14.

Teddy Wilson scored his maiden Super try, dummying and beating the line for a neat five-pointer late in the contest for the visitors once the contest was dead.

But the Blues weren't done, Cameron Suafoa awarded a try to push them over the 50-point mark against the Waratahs for just the second time.

Blues captain Patrick Tuipulotu was still dirty his side allowed three tries.

"We'll be happy with a win, but a lot to work on," the lock said.

"We managed to stay composed, build on longer phases and with our counter (attack), we were able to break through and get some points from there."

In his first Super Rugby start, Waratahs fullback Harry Wilson left the game in the second-half after failing a head injury assessment.