England captain Heather Knight is braced for the “biggest mental challenge” her side will face as they return to Test cricket against South Africa hoping to secure key Ashes preparation.

England conclude their all-format tour in Bloemfontein on Sunday, live on Sky Sports Cricket (8am first ball), having swept the T20I series 3-0 and won the one-day international leg 2-1.

Knight’s team have not played a Test match since a 347-run defeat in India a year ago but their next red-ball action after the South Africa clash comes against Australia at the end of January.

That fixture at the Melbourne Cricket Ground concludes the multi-format Women’s Ashes and Knight says England already have “one eye” on Australia in the new year.

Cross still being assessed after back spasm in final ODI

The tourists will play an extra bowler against the Proteas so as to protect their attack ahead of The Ashes, while seamer Ryana MacDonald-Gay is on standby should Kate Cross fail to recover from the back spasm she suffered in Wednesday’s final ODI.

Knight told reporters on the eve of the Bloemfontein Test: “I think mentally it’s probably the biggest challenge, getting your head around doing stuff for longer.

“I think it can be quite daunting to look at the game as a whole because we don’t play very much longer-form cricket, so trying to break it down is really important.

“Going into that Ashes Test match early next year, we want to use it as an opportunity to ask loads of questions, grow as individual players and work out that mentality.

“We’ve had had one eye on The Ashes throughout this series and trying to prep for that while trying to be successful in the here and now and not looking too far ahead.

“It’s been a brilliant trip for us with loads of learning and things we can fine-tune before we go into The Ashes. It will be a perfect end and a lovely Christmas present to get a Test match win.”

‘I don’t want us to have a blocking mentality’

On her love of Test cricket ahead of her 13th appearance in the format, Knight added: “I think it’s just such a test, and a really good learner for young players.

“The repetition of skill, the adapting to so many different situations that you might face. I think it’s a really pure format of the game.

“I’d love to see some domestic red-ball stuff, whether that be North versus South games as they’ve had a little bit in England previously, just to allow players to develop a little bit.

“A mistake I made earlier in my Test carer was thinking, ‘right, I’ve got to block it and leave the ball’. I don’t want us to have that mentality. It’s about reading the ebbs and flows of the game.

“When you get an opportunity to cash in and put the pressure on, you jump in. There may be times when we have to soak up pressure but that is the adaptability Test cricket is all about.”

Knight also confirmed Maia Bouchier will open the batting alongside Tammy Beaumont, as the pair did in the one-day international series, with Sophia Dunkley missing out on selection.

She added: “Picking a team is pretty hard, just because you’ve got minimal information and are going on white-ball cricket or a Test match that was maybe a year ago.

“I don’t think it should differ hugely from your one-day mindset. It’s just doing things for a little bit longer and managing situations that change in the game.”

England in South Africa – full schedule

T20 series (England won 3-0)

ODI series (England won 2-1)

One-off Test

• December 15-18 in Bloemfontein, live on Sky Sports Cricket from 8am Sunday