Alex Hales failed for the second time in consecutive innings on the second day of England's three-day warm-up match at Potchefstroom, leading his conqueror, the Zambia-born seamer Junior Dala, to claim he was "under pressure" going into his anticipated Test debut against South Africa at Durban in ten days' time.

Hales, who has been earmarked to open the batting alongside Alastair Cook in the Boxing Day Test, was bowled for 8 after a painstaking 42-ball stay, the same score he had made from just ten balls in the first innings.

Dala was the successful bowler on both occasions, this time inducing an inside-edge on to the stumps after extracting a touch of extra bounce from back of a length, having bowled Hales while offering no stroke first time around.

A supposedly stiffer challenge awaits later in the week, when the second warm-up against South Africa A gets underway in Pietermaritzburg on Sunday, but Dala's assessment hardly augurs well given that Dale Steyn, Morne Morkel and South Africa's newest fast-bowling talent Kagiso Radaba lie in wait for the first Test.

"I knew he hasn't played Test cricket yet so I knew he was under pressure," Dala told the Press Association. "I just came in and went hard at him, trying to expose the fact he is keen to score runs.

Dala's technical analysis was particular damning, and chimed with a similar assessment made by the former England coach Peter Moores, who claimed that Hales had been "found out" by the ball shaping back into him after he made an underwhelming ODI debut last year.

"It looks like he is trying to open up the off side every time he faces the ball. I just tried to keep it simple and tuck him up because he struggles on the leg side.

"In the first innings I was hoping I would bring one back, but I wasn't expecting him to leave it. Second innings was a bit back of a length, but the same plan, just tuck him up and he chopped it on.

"It's nice when a game plan comes together."

Dala added that he hopes his efforts will help the Test team to make their own plans for Hales later this month. "With the video analysis we do in cricket we felt we could expose a few of the English top order and maybe that could be good for the Proteas in the Test series."

However Chris Woakes, who returned figures of 1 for 35 in ten overs as the South Africa Invitational XI were bowled out for 188, played down concerns about Hales' aptitude for the challenge ahead.

"He probably hasn't had the time in the middle he'd like, but we're only two days into the tour and there's plenty of time to get into nick," he said. "He's a great player and he deserves his opportunity.

"Fingers crossed in the next week or two before the first Test he can get some more time out there and show what he can do."