The All Blacks are on a six-week, eight-match tour of South Africa, with four matches against provincial opposition and four Tests in the first of its kind in 30 years.
After starting with a far-from-convincing showing against the Stormers in Cape Town on Friday, the All Blacks proved devastating against the Sharks with eight unanswered tries, plenty of pace and few mistakes despite cold and wet conditions.
The Sharks had little answer to the All Blacks in Durban on Wednesday (AEST), with winger Fehi Fineanganofo scoring two of the tourists' tries.
The other six came from Damian McKenzie, Caleb Clarke, Jordie Barrett, Kyle Preston, Timoci Tavatavanawai and Sam Darry. Ruben Love put over seven conversions.
The Sharks put on 44-year-old former All Black Ma'a Nonu for the last 20 minutes after he recently joined the provincial side in a leadership and mentorship capacity.
Nonu, who won 103 caps for the Kiwis, performed a poignant solo response to New Zealand's traditional pre-match Haka to the delight of the crowd, then delivered some crunching blows on his compatriots in his cameo performance, one of the highlights for the 14,759 spectators at King's Park.
Former Wallabies coach Rennie has said he aimed to give all of his 44-man squad a run-out over the first three games, and after hammering the Sharks he added that the battle for places in the first Test side against the Springboks on August 22 was heating up.
"We've now had five games this season and I think we've got a lot better understanding of the game we're trying to play," said Rennie, referring to last month's Nations Championship wins at home to France, Italy and Ireland.
"We've got a lot more people who have got good (game) time and so we shared the load a bit, but there's a really good competition for spots, and so I think that's really important heading into the Tests.
"We're trying to build, however the conditions probably made it challenging to shift a lot of ball, but I thought overall we did a pretty good job out there and on the back of a really solid defensive effort.''
" We can't afford to start games like we have in the two games here, so that'll be a focus for us. In the first 40 minutes we gave away a lot of penalties early and just didn't build enough pressure for long enough.
"But the second half was excellent. We kicked really well, a lot more clinically. We continued to defend well. It wasn't always perfect, but we got a lot of reward from good work."
The All Blacks next meet the Bulls in Pretoria on Saturday.
