Jason Roy clicks as Surrey maintain winning start despite Marnus Labuschagne 74

Bowlers, beware: Jason Roy has got his mojo back. Surrey's margin of victory at the Kia Oval should have been much bigger than five wickets as they won their third game out of three in the Vitality Blast, but a middle-order wobble obscured the fact Roy had killed the game as a contest inside four overs of the chase; Glamorgan, who once boasted a proud record of six T20 wins in a row at this ground, had Marnus Labuschagne's third consecutive fifty to thank for sparing their blushes.

Roy's personality does not lend itself to bio-bubbles and "secure team environments" and his form has suffered at times over the last 12 months, with a rare lean patch in ODIs and scratchy form in both the Big Bash and England's T20I series in India and South Africa. Last week, he started the Blast with an ugly innings of 45 off 42 at Lord's, swinging rustily and being outscored by a ratio of five-to-two by Will Jacks, then thrashed a cameo of 30 off 14 at Taunton.

But here, in front of 4000 or so supporters, he scoffed at Glamorgan's plan to start with spin against him in the Powerplay, racing to 41 off 18 balls. "I always look for small progressions," he said afterwards. "Lord's was very scratchy and I didn't have that rhythm, hitting a lot of fielders and just getting a bit frustrated. At Taunton I had a bit of fun after a four-and-a-half-hour journey - I thought 'why not?' But tonight, it was a lot better."

Roy had dumped the first ball he faced straight back over Prem Sisodiya's head for four and the second over of the chase demonstrated his dominance over bowlers at this level. Andrew Salter, the offspinner, went full and straight to start with, so Roy cleared his front leg and smeared him over mid-off. Roy realised the second would be shorter, so rocked back and slapped a cut through point with a powerful snap of the wrists. Salter had nowhere to go, and went full again; Roy lined him up, and hammered him straight back over his head.

He was quieter against Glamorgan's seamers, but still brought up a 28-ball half-century off the final ball of the Powerplay. When Labuschagne was introduced, Roy swept his first ball hard for four, and belted his third over midwicket; the only surprise came in Labuschagne's second over, when he miscued a skier to backward point via a thick top-edge.

"Someone has to get you out at some stage, don't they?" Roy said of Glamorgan's ploy to bowl spin at him up front, which has become a consistent plan against England in T20Is. "Sometimes it happens to be a left-arm spinner. A leggie got me out tonight eventually, didn't they? So I'm sure someone will have something to write about. As a player, it gives you something to work on, which is always nice."

Roy's innings took the equation from 167 off 120 balls to 79 off 71 by the time he was dismissed, effectively sealing the game despite their minor stumble. Sam Curran and Jamie Overton fell in successive overs after Roy's dismissal before Laurie Evans drilled Sisodiya straight to long-off, but Jamie Smith's cool-headed 35 not out saw them across the line with 10 balls to spare.

Roy will play two more games for Surrey, at home against Sussex and Hampshire on Thursday and Friday, before he links up with England on Saturday ahead of their white-ball summer, which comprises six ODIs and six T20Is, three each against Sri Lanka and Pakistan.

"You always go back to square one, no matter how many runs you've scored," he said. "Before every series you go back to the drawing board and get yourself back to basics and go from there - you certainly don't want to think that you're going to score runs every game, because unfortunately that's not the way the game works. But it's obviously very nice to have these runs behind me - it makes it a lot easier.

"[Last year] was a huge experience and a massive learning curve. I've come through the other side a lot better for it. It was a very tough year on and off the field so it was about keeping my head down and making sure I stay consistent with my training and back myself, knowing that eventually it would come right. Am I in a good headspace now? Absolutely."

For Glamorgan, Labuschagne had been the glue holding the innings together for the third game in a row after Nick Selman's leg-side pick-ups had got them to 55 for 1 inside six overs. Surrey exploited match-ups to their advantage, with Gareth Batty and Dan Moriarty encouraging batters to hit towards the long boundary and Glamorgan duly obliging.

Labuschagne had stated his desire to use the Blast as a chance to pitch his case for inclusion in Australia's T20 World Cup squad at the start of the season and his early efforts have been persuasive: 93 not out, 59 and 74 tonight, giving him 226 runs for twice out at a strike rate of 146.75 and four cheap wickets to boot.

One of his biggest assets in T20 is his willingness to use his position on the crease to throw bowlers off their line, and his ability to adjust. There was no better demonstration than the fifth ball of the 17th over, when he jumped outside leg stump to encourage Tom Curran to bowl wide outside off, despite having point and third man up inside the ring. Curran landed a perfect wide yorker, but Labuschagne stretched out and deflected it away through the gap, like a centre-forward in hockey deflecting the ball in at the back post.

He had started slowly, eking out 17 off the first 22 balls he faced with Curran putting down a caught-and-bowled chance, but once Labuschagne had adjusted to the slowness of the pitch he was away, hitting 57 off the next 29. His slow start was put into perspective by Roy's fireworks, but with Surrey applying the squeeze, there had been no other option.