Chris Silverwood, England's head coach, has praised his young squad for finishing a rollercoaster Test winter on a high, but insisted that the gains made during a come-from-behind series win in South Africa are only the first step in a "two-year project" that culminates with the next tour of Australia in 2021-22.

Victory in Johannesburg capped a dramatic upsurge in form for England's Test team, which endured a 1-0 series defeat in New Zealand before Christmas before touching rock-bottom in the Boxing Day Test at Centurion, where an illness-ravaged squad were beaten by 107 runs to fall behind in their four-Test series in South Africa.

But from that moment on, and as the Benoni sickness bug was gradually shaken out of their systems, Joe Root's men found their poise with three wins in a row at Cape Town, Port Elizabeth and the Wanderers, where Mark Wood excelled with nine wickets in a fast and furious Player-of-the-Match performance.

"It's been quite a journey since we arrived in South Africa," Silverwood told Sky Sports. "Obviously to go from the build-up to the first Test, and the result of that first Test, to get to where we are now, is really pleasing.

"[The illness in the squad] was tough but you can't use it as an excuse," he added. "The one thing it did do, was it pulled us together as a unit. We had a good chat in the dressing room after the first Test, and you could see the determination on the guys' faces. So I wasn't surprised when they came out and played as well as they did, but I'm obviously very proud of them."

Given that Silverwood had also flown home early from New Zealand due to a family bereavement, he might have been entitled to wonder what he had signed up for, after taking over from Trevor Bayliss at the end of the English season. But, he insisted, the groundwork that England laid on those flat decks in Mount Maunganui and Hamilton was integral to England's subsequent success.

"We started something in New Zealand, and you can see the blueprint that we said we wanted," he said. "Big first-innings runs, and we were also learning to take 20 wickets with the Kookaburra ball. So to see it come to fruition - to see some of the youngsters come through and put their hands up, and for the older guys to do the same - is obviously really pleasing."

The success of England's core of new players was the clear stand-out feature of the series. Dom Sibley's century at Cape Town helped turn the series, while his opening partnership with Zak Crawley went from strength to strength; Ollie Pope and Dom Bess played integral roles in the Port Elizabeth win, while Sam Curran chipped in with key runs and wickets throughout.

But Silverwood was particularly pleased with how England's variety of batting styles helped to ensure regular 400-plus totals.

"To get a batting order that has the ability to get big first-innings runs, you need to create a variation in how they are going to play," he said. "So you can see the one, two, three we've got [Sibley, Crawley and Joe Denly] go about things in their way, which is completely different to how Rooty, [Ben] Stokes, Pope and [Jos] Buttler will go about their business.

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"I think there's a nice mix of skills in there, which allows us to have a top seven to build big totals, and equally we've seen how the lower order can then be entertaining as well. You saw Woody and Broady here [with an 82-run stand for the tenth wicket]. If you build the platform, anything can happen."

Wood's raw pace was England's big find in the final two Tests. He managed to play back-to-back matches for the first time since 2017, and gave the impression that a new, extended run-up has taken some of the strain out of an action that previously seemed to invite regular injury setbacks.

Silverwood, however, said that England would continue to monitor his fitness on a game-by-game basis, to help ensure that he is able to give his best efforts on the field more regularly. He even hinted that Wood and Jofra Archer, currently labouring with an elbow injury, might be used on a rotational basis in future Test outings.

"We will make to make decisions based on what's best for him," Silverwood said of Wood. "We will look at how he trains as well, making sure he's not wasting all his best deliveries in the nets. Whatever he does, he does it 100 percent. So can we tailor his training to make sure that his best effort goes out on the pitch for us, and equally when he needs to rest, we'll know we've got a backup with Jofra and others to come in."

"It's a great headache to have for Rooty as captain and me as head coach," Silverwood added. "In an ideal situation, we'd like to have two or three fast bowlers kicking around but we don't have to play them every game. In this Test, Woody comes in and makes an impact, but another day, we can give him a day off because we've got Jofra coming in now."

With England's next tour of Australia looming in just under two years' time, Silverwood earmarked Jamie Overton and Olly Stone as the types of 90mph back-up with which England will be looking to augment their squad, and compete with the established names, such as James Anderson, Stuart Broad and Chris Woakes.

"We've got these guys to nurture and bring through in a two-year project, for when we get out there [to Australia]," Silverwood said. "But also we've got to look after the guys we've got.

"As we've also seen in this series, your Andersons, your Broads, your Woakeses. I wouldn't want to dismiss them lightly. Chris has trained so hard all trip. He got his opportunity here and showed once again he's a class act."