When Patel finally fell, edging Josh Davey behind after a superb 133-ball innings featuring 14 fours and plenty of judicious attacking intent, much of the hard work had been done
Kia Oval (fourth day of four): Somerset 337 & 207; Surrey 308 & 239-7 - Surrey win by three wickets
Ryan Patel continued his fine start to the season with a match-winning 102 as Surrey confirmed their position as the LV= Insurance County Championship's early pace-setters by beating Somerset by three wickets at the Kia Oval.
Surrey, needing 237 to win a fiercely-contested Division One match, completed their second victory from the first three games just before 5pm on the final afternoon, with Patel joined by Ben Foakes in a decisive fourth-wicket partnership of 66.
Foakes was earlier passed fit to resume playing after concussion tests, following his nasty collision with first slip Jamie Overton on day three, when both players dived for an edge from Tom Banton. Foakes somehow managed to hold on to the ball despite hitting his head hard against Overton's shoulder and, after lengthy treatment, leaving the field with a cut under his right ear.
But Foakes played skilfully for 48 not out after joining Patel at 106 for 3, Surrey having just lost both Hashim Amla, for 14, and Ollie Pope, for five, in the first half-hour after lunch.
When Patel finally fell, edging Josh Davey behind after a superb 133-ball innings featuring 14 fours and plenty of judicious attacking intent, Surrey's total had reached 172 and much of the hard work had been done.
Certainly, without Patel's aggressive knock, his second championship hundred and a career-best, Surrey's chase would have been far trickier than it already looked on a pitch still giving the bowlers enough reasons for optimism.
Sam Curran's breezy 33, including two sixes immediately after tea off Jack Leach, helped Foakes to steer Surrey across the finishing line, although there was a final stutter when Curran edged Jack Brooks behind, Will Jacks (1) carved Craig Overton, bowling despite a bruised toe, to gully and Jordan Clark slogged Brooks to mid-on to go for six with only three runs required.
It is a sorry seventh successive championship defeat for Somerset, going back to the end of last summer. Surrey take 21 points and Somerset six.
Jamie won the battle of the Overtons (Ben Hoskins/Getty Images)
Starting the final day on 196 for 9, a lead of 225, Somerset's last pair Davey and Brooks added only another 11 runs in 3.3 overs before Davey edged a Clark away-swinger to first slip to go for 12. Clark finished with the impressive figures of 4 for 52.
Patel and Rory Burns batted positively from ball one of Surrey's chase, with skipper Burns taking two fours from Overton in the third over – first slicing him to third man and following it up two balls later with a far more authoritative square drive.
Peter Siddle beat Patel early on with a magnificent ball, but the left-hander responded by hitting him through square cover for four and then taking several more eye-catching boundaries in quick succession off Somerset's new-ball bowlers. First he straight drove Siddle for four before, in the space of three balls, pulling and slapping high over mid-off when Overton twice pitched short.
Burns top-edged an attempted hook at Overton high over the keeper for four, but the former England Test opener was less fortunate when on 17 he went after another short one, this time from Brooks' fifth ball, and skied to Davey at wide long leg.
Amla got going with a leg-glanced four off Brooks, and the seamer suffered further punishment as Patel pulled, extra cover drove and swatted through midwicket to collect three more fours.
Patel reached fifty from 60 balls, just before lunch, but Amla departed soon after the interval when Siddle – with the fourth ball of his second spell – found some extra lift to have the former South Africa great held by keeper Steven Davies, the ball looping up gently after Matt Renshaw failed to hold on to the edge at second slip.
Pope cut to gully a ball from Brooks that was too close to him for the stroke, and Tom Abell took a smart tumbling catch to bring Somerset right back into the contest. Thanks to Patel, Foakes and Curran, however, it was Surrey's day.