Durham 402 (Clark 109, de Lange 5-95) and 158 for 1 (Cook 89*, Steel 51) beat Glamorgan 295 (Selman 103, Rushworth 5-52) and 263 (Ingram 70*, Carey 49) by nine wickets
Durham coasted to their first Specsavers County Championship win of the season when they made light work of reaching a target of 157 in 43 overs against Glamorgan at Chester-le-Street.
After making only one half-century in his 13 previous championship innings, Stephen Cook led the way to the nine-wicket win with an unbeaten 89 from 78 balls in his final appearance before linking up with the South Africa Test squad next week.
Cameron Steel also went for his shots from the outset and survived three difficult chances in making 51 off 58 balls as Durham got home with 18.3 overs to spare. Cook worked the ball into leg-side spaces before cutting Marchant de Lange to the rope as he scored 34 of the 54 runs that came up in the first ten overs.
With their seamers making no impression, Glamorgan turned to Andrew Salter's off spin and Cook drove him wide of mid-off for his sixth four to reach 50 off 49 balls. Two similar strokes for his eighth and ninth fours brought the winning runs.
Only 28 were needed when Salter persuaded Steel to chip a catch to deep mid-off, allowing Jack Burnham to assist in completing the task with an unbeaten 14.
After resuming on 92 for 2, Glamorgan were dismissed for 263 in their second innings, with Colin Ingram left unbeaten on 70, made off 137 balls with seven fours and a pulled six.
Barry McCarthy finished with 4 for 65 after briefly coming under fire from nightwatchman Lukas Carey.
After conceding 16 runs in 11 overs, McCarthy went for 26 in two, which included a six over long-on.
But when he needed one for his second half-century in successive games, Carey got carried away and had his stumps splattered by an inswinger from Chris Rushworth.
Three wickets had gone down for five runs in three overs when McCarthy pinned Aneurin Donald lbw with a shooter and had David Lloyd well caught at second slip by Ryan Pringle off an edged drive.
Ingram survived a difficult chance to Steel at cover off McCarthy, but was otherwise untroubled and was kept company for 16 overs after lunch by Tom Cullen on his championship debut.
But after making 13 he shouldered arms and lost his off stump to a Rushworth inswinger in the sixth over of the new ball.
Marchant de Lange threatened to take it away from Durham in a ninth-wicket stand of 40 in six overs. But Rushworth clung on to a return catch from a fierce drive then, three overs later, Michael Hogan played across the line and was bowled off his pads by McCarthy.