Ben Youngs insists England have received a valuable lesson in time for the World Cup that will not be allowed to happen again.

Eddie Jones' men were caught unaware at the Principality Stadium on Saturday as Wales' quick-thinking exploited a moment of confusion to engineer a crucial try that secured a 13-6 victory.

Anthony Watson was in the process of leaving the field having been sin-binned for a deliberate knock-on at a time when Ben Youngs was waiting on the sideline to replace Willi Heinz, who had departed for an HIA.

Reduced to 13 men in the 32nd minute, they were ambushed by a quickly-taken penalty that saw Dan Biggar expertly launch twin kicks to each wing to enable George North to stroll over.

England were expecting referee Pascal Gauzere to wait for Watson to exit before restarting play, while the delay to Youngs' arrival was also unsettling. But the veteran Test Lion recognises his own team were at fault as well.

"Being down to 13 men is never ideal. Anthony came off and then the boys are in a huddle. Then Willi has come off and I'm waiting to be given the green light to go on," Youngs said.

"Before I know it, Wales are off. It's happened here and I dare say something like that will not happen again. It's one of those things.

"There's nothing as players that you can do about that except take the one lesson which is don't switch off when there's a penalty."

England can feel aggrieved, however, that on two occasions in the second half Gauzere pulled back Youngs when the Leicester Tiger attempted his own quickly-taken penalties.

"Dan Biggar is a tremendous kicker of the ball, looked at that opportunity and took it," Youngs said.

"I tried to tap later on in the game and for whatever reason – I don't know if it had been planted in his (Gauzere's) head that he didn't want anything like that to happen again – but I wasn't allowed to go.

"It is what it is. As long as it's ironed out and doesn't happen in the future I'm sure it will be fine."

North's superbly-executed try was the main talking point from an arm-wrestle of a second instalment of the rivals' two tune-up Tests for this autumn's World Cup.

Wales – potential quarter-final opponents in Japan – avenged their defeat at Twickenham six days earlier but little was learned by either team in a match that served the main purpose of giving players game time.

"We're going into these internationals without much on the menu in terms of attack – strike-wise – because you don't want to show much," Youngs said.

"It tests us when you keep going back to the same moves and the same things, but that's fine.

"We seem to have cracking encounters with Wales and they tend to be very physical and there's no lack of that.

"If we both get to the quarter-finals, then I'm sure it's a fixture that a lot of people would look forward to."

England's injury issues are gradually clearing up, headlined by prop Mako Vunipola's return from a three-month hamstring injury against Ireland on Saturday.

The hamstring issue that forced wing Ruaridh McConnochie to withdraw on the morning of the game should clear-up within 10 days, while flankers Sam Underhill and Tom Curry could be back from their toe and shoulder complaints in time to face the Irish.

Back row Mark Wilson is also making good progress with his rib injury, while wing Jack Nowell and centre Henry Slade are looking at comebacks for Italy on September 7 as they deal with ankle and knee problems.