All Blacks senior assistant coach Neil Barnes has directed sharp criticism at referee Karl Dickson following South Africa's 43-28 victory at the M&T Bank Stadium in Baltimore on Saturday, a result that handed the Springboks a 3-1 series win in the Greatest Rivalry tour.

The Boks ran in six tries to the All Blacks' four in front of a USA rugby record crowd of 68,000-plus, but Barnes was in no mood to offer straightforward credit, instead arguing that the world champions benefited from favourable officiating throughout.

"Every time they keep getting penalties for bugger all and get to slow the game down, it brings them back into it," Barnes told Newstalk ZB. "We get two penalties against us at the start of the game for a brake foot, which no one really gives a s*** about, but the referees are concentrating on. And when you look at the video, both teams have done exactly the same thing at the same time. There's two penalties against us."

Barnes acknowledged the Springboks' quality while framing the performance gap as partly a product of refereeing fortune. "At the end of the day, there's a perception there that they are the dominant team, but at the moment they're getting the rub of the green. When that changes, we'll have a fair go."

He did concede, with some reluctance, that the better team won on the night. "Clearly they're probably, fair to say, the better team tonight. But holy heck, there's a couple of moments swinging with about 20 minutes to go where two or three times in a row we have come out on the wrong side of a close call which let them skip away from us a little bit."

Despite the 3-1 series defeat — the All Blacks having spent six weeks in South Africa before the Baltimore finale — Barnes maintains the side is closing the gap on the world champions under Dave Rennie. "The more I reflect, the more I know we're seriously close to them. We're playing against one of the best teams in the world and probably one of the best ever and at the moment they've got our number, but we're not far away from them."