By Nick Said

JOHANNESBURG (Reuters) - Captain Richie McCaw conceded New Zealand had to "dig deep" in their frenzied 38-27 victory over South Africa at Ellis Park on Saturday that saw them retain the Rugby Championship title.

New Zealand scored five tries on their way to the bonus point win in a game where the lead changed hands with regularity and the All Blacks had to play for 20 minutes with 14 men following yellow cards for Liam Messam and Ben Franks.

The showing was all the more impressive in that New Zealand arrived in Johannesburg on Monday from Argentina, acclimatising quickly and showing no adverse effects from the altitude at which they were playing.

"We had to dig deep, both teams came here willing to play," McCaw told reporters. "We had 20 minutes with 14 men, add into that a bit of travel, it was a very satisfying win.

"Going behind we could easily have got flustered, but the guys hung in there. We took our chances really well and there were times when we were under a lot of pressure and then got a critical turnover."

McCaw believed Messam's try after the siren at the end of the first half that took the All Blacks into the break 21-15 up was the crucial moment in the game, a point reiterated by Springbok coach Heyneke Meyer.

"The try on halftime was critical, I'm sure it changed their halftime talk," McCaw said. "But credit to the Boks, they came out in the second half and scored again quickly, though we were able to keep ourselves ahead in the game."

The All Blacks skipper felt there was not much to choose between the two sides and praised the home side for keeping coming at them.

"There is very little between these teams and they put us under a hell of a lot of pressure. It's the same every game I have played against the Boks, if you don't get it 100 percent right you are in trouble."

McCaw, who hoisted aloft the World Cup trophy in 2011, ranked Saturday's win among his best in an international career spanning 120 matches given it was achieved at what New Zealand considers South African rugby's spiritual home.

"These are ones you want to play in, this is why you play the game of rugby. Growing up there are places you want to play and to get a chance today and to get a win here is pretty special, I remember watching the 1995 World Cup final (South Africa beat New Zealand 15-12) and thinking that one day it would be awesome to play there."

New Zealand's next assignment is their final Bledisloe Cup match against Australia in Dunedin on October 19, though they have already retained that title from last year as well.

(Reporting by Nick Said; editing by Amlan Chakraborty)