The disappointing 20-22 loss in Washington was the Springboks’ third successive loss to the Welsh Dragons and got Erasmus’ tenure off to the worst possible start.
Erasmus said he was ‘disappointed’ to see his team lose at the death.
“We didn’t get the result we wanted and that’s disappointing because no one ever wants to lose a Test match,” Erasmus said.
“There were a lot of defensive errors and we have to improve.
“All three of Wales’ tries came from kicking errors and overall it was very tough.”
The game in the American capital had its critics, with both sides fielding inexperienced line-ups ahead of their Test series with Argentina and England respectively.
A penalty from Robert du Preez looked to have given the South Africans victory, but the replacement flyhalf then had two consecutive attempted clearance kicks charged down by Tomos Williams and Ryan Elias pounced to win the game.
Erasmus, the new head coach as well as the South African Rugby Union’s Director of Rugby, offered no excuses.
“We knew there would be risks involved by only coming over later in the week, but we’re not making any excuses – the Welsh showed more determination in the end to clinch the game,” said Erasmus.
“All their tries were scored as a result of kicking – a charged down kick and box kicks we failed to control – and also we committed some defensive errors.
“We had our chances to score, and overall I think it was the pressure, which they were able to put on us at the end, that won it for them.
“The one positive for me is that there were quite a few new players who got caps today and now know what it’s like to play against a quality team like the Welsh, but it’s still a Test that we lost, and that hurt.
“It’s never nice when you play you first Test and you lose, and we didn’t want that result, but we wanted to get all of the uncapped players on the field and start building towards the future.
“However, we still lost and that almost nullified the fact that we capped a lot of new players.”
Looking forward to the three-match Test series against England, which starts next Saturday in Johannesburg, Erasmus said: “We will have to step up against England.
“We know the pressure will be on us to win, just as they would also be under pressure to be successful following their recent results.”
Pieter-Steph du Toit, who captained the Springboks in the US capital, said that despite the negative outcome, the squad will ultimately benefit from the match against Wales.
“We managed to work our way through a lot of detailed preparation so that it can also benefit us for the series against England,” said Du Toit.
“Going into the change room at 14-3 down, we realised that the first half was not good enough and that we needed to step up after the break.”
The Springboks will arrive back in South Africa on Monday to start preparations for the first Test against England at Ellis Park this coming Saturday.