Surrey 83 for 0 (Burns 44*, Sibley 37*) trail Lancashire 204 (Hurst 46, Clark 4-57) by 121 runs
Rocky Flintoff made a creditable 32 on debut, as Lancashire's youngest first-class cricketer at the age of 16 years and 137 days, but it was champions Surrey who ruthlessly took first-day honours at the Kia Oval.
Put in, Lancashire were bowled out for 204 inside 59 overs, with no one making it to 50, and Surrey then replied with 83 for no wicket before bad light ended play 15.4 overs early. Skipper Rory Burns was 44 not out, including straight driving George Balderson's medium pace for successive fours, and Dom Sibley unbeaten on 37.
Jordan Clark (4 for 57) and Dan Worrall (3 for 31) continued their fine red-ball seasons by spearheading a five-pronged seam attack in which Conor McKerr also took two wickets and Sam Curran one in what was, for both, their first Vitality County Championship appearance of the summer.
Matty Hurst, with 46 from 64 balls, played Lancashire's best and most assertive innings, while Balderson's 33 and Josh Bohannon's 26 were other worthy efforts in seam-friendly overhead and pitch conditions.
But most eyes were on Flintoff, who made 167 runs in seven Metro Bank One-Day Cup innings after becoming his county's youngest player in any format last month, and who came in at 33 for 2 in the 11th over after both Luke Wells and Keaton Jennings had fallen to the new ball.
Wells went in the fourth over for 9, dragging an attempted off drive into his stumps against Clark, while Jennings looked aggrieved to be given out leg-before for 12, pushing forward to an inswinger from Worrall.
Off the mark first ball, clipping Worrall confidently for two off his pads, young Flintoff was soon living up to his reputation as one of the best players of his age to emerge in recent decades - on a day when most 16-year-olds around the country were more concerned about getting their GCSE results.
Uncannily like his father Andrew in build and mannerisms - the former England captain and television celebrity was watching proudly from a hospitality box - the young Flintoff saw off Worrall's fine opening spell of 7-3-9-1 and helped Bohannon to add 40 for Lancashire's third wicket in tough, overcast conditions.
He did have some moments of good fortune, being dropped at third slip on 13 when he edged Tom Lawes and later also flailing a returning Worrall just over the cordon for four as lunch approached, but otherwise he looked comfortable at the crease and mature beyond his years as Lancashire reached lunch on 98 for 3.
Bohannon had gone by then, chopping on to McKerr for 26, and unfortunately for Flintoff he sliced a drive at the first ball after lunch, and his 64th - from Clark - and saw Sai Sudharsan dive forward at backward point to scoop up a brilliant catch.
Hurst played some superb shots but was dropped by Clark from a skier on 45 before McKerr dived to his right to hold a magnificent low catch at leg slip in Curran's next over and from 155 for 4 the Lancashire first innings fizzled out as Worrall, McKerr and Clark combined to overpower the tail.
Indian all-rounder Venkatesh Iyer, on his Championship debut, played one memorable cover drive before optimistically jumping down the pitch to swing at Worrall and edge behind while Balderson, playing defensively, nicked the same bowler to first slip.
McKerr's pace and lift did for Tom Hartley, caught at the wicket for 5, and only some defiance from Tom Aspinwall - who hooked McKerr for six and extra cover drove him for four in a bright 23 not out - took Lancashire past 200 before they lost both Josh Boyden, who lifted a simple catch to mid off on 5, and Will Williams, caught behind, from successive deliveries from Clark.
