Head coach Eddie Jones has warned that England must improve their set-piece to ensure their victory over world champions South Africa is not a false dawn.

Jones’s “new England” project got off to the best possible start with an autumn clean sweep, capped by a stirring 27-26 victory against South Africa on Saturday. A 79th-minute Marcus Smith penalty got England over the line having been on the back foot for most of the second half with the Springboks dominating the scrum and maul.

There was little triumphalist tone in Jones’s review of the autumn with an acknowledgement that the Springboks may have been “mentally fatigued” after nearly four months away from home. And while he embraced the strides taken in attack, Jones insisted his team needed to evolve further to fulfil their stated goal of winning the 2023 World Cup. 

In particular, he highlighted the set-piece and the breakdown – where England conceded eight of their 18 penalties against South Africa – as prime areas of concern.

“The evolution of the side is to become more consistent in the application of our skills,” Jones said. “We are not strong enough in the set-piece to beat a side like South Africa consistently and that is going to take a lot of work to get our scrum and our maul particularly to the level we want it to be to add another string to our bow.

“While we’ve had good results, our performance is still at a level where there’s a lot of improvement in us, but the great thing is that we’ve got four campaigns until the World Cup in 2023 so the next campaign, which is the Six Nations, is a great opportunity for us to keep improving. [The results] doesn’t hide the fact that there are areas of our game that we need to continually improve, particularly around the consistency of our set-piece. The breakdown is providing more challenges as the weeks go by and we need to get better in that area, but they’re opportunities for us to improve in.”

Aside from the three victories over Tonga, Australia and South Africa, Jones’s greatest delight has been in the integration of a new generation of young players with the older heads. Jones has handed out 23 new caps over five Tests with fly-half Marcus Smith and full-back Freddie Steward taking to international rugby like ducks to water.

A lot of team-building was conducted in their training camp in Jersey in which players engaged in the Japanese purification ritual of “misogi” as well a paddleboarding competition. Jones confirmed he would continue those elements in the Six Nations but admitted he was at a loss to explain why it worked so effectively in this campaign.

“I was talking to a coach who won a major, major trophy four or five weeks ago,” Jones said. “I said, ‘What did you do?’ He said, ‘I really don’t know, every team I get I do the same thing and sometimes it works and sometimes it doesn’t’.

“We do the same things we always do, we encouraged them to work together, we encouraged them to train hard. For some reason there was this chemistry in that group, and it just took off. And when you have that nice feel they tend to fight a bit harder, they dig down a bit deeper. Because the tank is never empty. Sometimes you think it’s empty. They were able to find a lot of extra petrol in the tank on Saturday, and a lot of it we don’t know why.”

Jones repeated his message that the door was not shut on the likes of George Ford and the Vunipola brothers, who were dropped from this autumn campaign. “It’s all about performance, how they present themselves physically, they are all indicators of how much desire you’ve got,” Jones said.

Captain Owen Farrell faces a race against time to be fit for the start of the Six Nations after sustaining an ankle injury that caused him to miss the South Africa victory. Jones, who typically picks his captains from campaign to campaign, would not confirm whether Farrell would remain the leader of “new England” entering the Six Nations. “We’ll worry about that selection when selection comes.”