Surrey 339 for 8 (Clark 107, James 4-74) vs Nottinghamshire
The all-rounder hit 107, sharing a seventh-wicket partnership of 97 with Sean Abbott to steer the home side, who had stuttered to 70 for four after being put in, to 339 for eight at stumps.
Nottinghamshire lost seamer Jake Ball to injury in the first session and their problems were later compounded when fellow opening bowler Brett Hutton limped off with cramp. Hutton, who had earlier increased his season's tally of wickets to 36 - the joint-second highest in Division One - attempted to resume bowling towards the end of the day, but pulled up again after only a single delivery.
Haseeb Hameed, taking over Nottinghamshire captaincy duties after Steven Mullaney was ruled out by a side strain, won the toss and chose to bowl - a move instantly vindicated when Hutton trapped Rory Burns lbw for a second-ball duck.
Hutton also sent a few deliveries fizzing just past Tom Latham's outside edge but the visitors were unable to make further inroads, despite rotating their trio of frontline seamers - a stock that became more limited when Ball left the field after five largely unproductive overs.
That situation swiftly changed as three wickets went down in a shade under three overs, with Hutton returning at the Vauxhall End and getting the ball to seam and take Sibley's outside edge.
Wicketkeeper Tom Moores sprang smartly to his left to take the second of his five catches in the next over, dismissing Jamie Smith for a duck off James, who bowled resolutely and also had Latham leg before moving across his stumps.
Will Jacks initiated a counter-attack in the afternoon session, dispatching both Hutton and Dane Paterson to the mid-off boundary as he and Ben Foakes swiftly built a partnership of 60 for the fourth wicket.
But a shrewd bowling change again paid dividends, with Paterson beginning a new spell and persuading Jacks to give his first delivery the charge, resulting in a thick edge that thudded into Moores' gloves.
Clark eagerly accepted the baton and soon overtook his partner, looking strong off the back foot and crashing Paterson for two cover boundaries before chopping him through point for four more.
However, Hutton's mid-over exit shortly before tea compelled Nottinghamshire to give leg-spinner Calvin Harrison an extended spell, with Matthew Montgomery also turning his arm over.
Clark nudged a single to reach his 50 shortly after tea, only for Foakes to feather Paterson's next ball behind and fall four shy of that landmark, yet Abbott proved a more than capable ally.
Hutton eventually rejoined the attack midway through the last session, but Abbott clubbed his first ball to the fence before the bowler pulled up in his next delivery stride and trudged back to the dressing-room once more.
Clark progressed towards the third first-class hundred of his career and got there from 133 balls, coming down the track to smash Montgomery to the mid-on boundary before James had him caught behind soon afterwards off an inside edge.
Abbott looked set for a half-century, thumping James for successive fours to reach 48, but he slashed the next ball to second slip to give the Nottinghamshire all-rounder his fourth wicket of the innings.