Wales coach Warren Gatland cast doubt on England's ability to win the games that count after his side came from behind to defeat their arch-rivals 21-13 in a dramatic Six Nations contest in Cardiff on Saturday. Gatland's men were 10-3 down at the break after England flanker Tom Curry scored the only try of the first half. But they 'won' the second period 18-3 to stay on course for a Grand Slam and set a new Wales record of 12 Test victories in a row, breaking a mark that had stood for 109 years. Gatland, who had overseen a record 30-3 Wales win over their border foes to deny England a Grand Slam in 2013 and was in charge when they beat them at the 2015 World Cup -- a result that contributed to the tournament hosts' first-round exit, questioned the big-game resolve of the Red Rose brigade ahead of this year's World Cup in Japan. "I look back on England in the last few years. When it's really mattered, I've questioned whether they can win these big games," said Gatland. "We've had a record of being pretty good in them," the New Zealander added. Early in the second half, fly-half Gareth Anscombe kicked two penalties, both conceded by England prop Kyle Sinckler, to cut the deficit to 10-9 before the visitors went further ahead at 13-9 through captain Owen Farrell's 63rd-minute penalty. But Wales stormed back, with powerhouse wing George North's break setting up a try for lock Cory Hill that replacement fly-half Dan Biggar converted to make it 16-13. Biggar then provided a pinpoint cross-kick from which wing Josh Adams scored the clinching try two minutes from time to spark delirious scenes at the Principality Stadium. England had won away to champions Ireland in their tournament opener before thrashing France 44-8 at Twickenham last time out. "We're in a good position because you guys (the media) were all talking England up, saying there was going to be 15 points in it," said Gatland, who will stand down as Wales coach after the World Cup. "We knew exactly where we were and I said to the players they (England) had no idea what animal was turning up this week but we did." Gatland explained the signs that Wales had a huge performance in them were evident from the way they had trained in the run-up to Saturday's match. "It was probably one of the best weeks that I've had with the team," said former Ireland coach Gatland, whose first game in charge of Wales was an even more remarkable win over England in 2008 that saw his team come from 16-6 down at half-time to triumph 26-19 at Twickenham. "I've been involved with a lot of teams and yesterday's captain's run was as good as I've ever seen," said Gatland. - 'Forgotten how to lose' - Wales started this Six Nations by coming from 16-0 down at half-time to beat France 24-19 in Paris -- a result that becomes increasingly important with every week of the tournament. "We said before we left the hotel that we would win today (Saturday) because we've forgotten how to lose," said Gatland. "I'm very proud of the boys and it was a great performance and they should enjoy their party tonight," he added, with Wales continuing their Six Nations campaign away to Scotland, beaten 27-10 by France in Paris on Saturday, before finishing at home to Ireland on March 16. "I thought we finished really strongly. I knew we were right mentally, but we still have some improvements in our game."