Jones' men followed up their dramatic 38-34 win in San Juan a week earlier with a more assured 35-25 victory in the second Test in Santa Fe to register an eighth successive win over the 2015 World Cup semi-finalists, who will also provide the opposition for England in Japan in 2019.
"If anything, it exceeded our hopes and expectations because we learned so much about ourselves and the development of the team", Hartley said. It was like a game of chess and they made the moves better than us.
The tourists, level at 25-25 with 16 minutes left, finished stronger as prop Will Collier barged over for a try that fly-half George Ford converted.
Eddie Jones named a youthful side for the second installment of the series, which included the likes of Harry Williams, Charlie Ewels, Tom Curry, Sam Underhill and Mark Wilson.
"It was an unbelievable effort, to have 20 new players on tour, but the collective effort from all the guys was wonderful as well. I think it has been a great Test series, some really good rugby and I think Argentina should be congratulated on the sort of rugby that they play".
"I think in each game we found a way to score points".
"I'd like to think Eddie is pretty chuffed as well".
"We want to become a very adaptable team - we want to be able to play both ways, if we have to slug it out or if we have to play in an open affair like it was last week". It was a big achievement, against an experienced Argentinian side in the rural parts, in hostile atmospheres. We also generated a lot and we had try options but, if you do not give speed to the game, you can not break these defences.
Piers Francis scores his first global try in England's 35-25 win over Argentina.
The England team will fly home from Buenos Aires on Monday but Hartley will soon be packing his bags again as he heads back home to New Zealand to visit his family.
Lions coach Warren Gatland caused a stir by calling up extra players from Scotland and Wales rather than England because they were already in Australasia.
"I thought Chris Robshaw and Mike Brown were absolutely exceptional", said 57-year-old Australian Jones, referring to two of the few "old hands" in the Santa Fe line-up. "You are always getting picked on", he said.
Ford restored his side's lead with a penalty but Nicholas Sanchez struck twice in quick succession to make it 13-10, the first of which was initially waved away by the touch judges but awarded by referee John Lacey after consulting with the television match official. "He had a terrific game last week but he is still a bit battered and bruised and sometimes you are better off giving him a break now and get his off-season in and he will be right to go next season".