Glamorgan 133 for 5 (Rutherford 58, Reingold 40) beat Surrey> 132 (Clarke 35, Salter 3-37) by five wickets
Glamorgan made it three wins from five Royal London Cup matches and stayed in the hunt for qualification for the knock-out stages with a five-wicket hammering of Surrey.
This was Surrey's first defeat of the competition as they had a day to forget. The visitors won the toss and chose to bat on a glorious Cardiff morning, but Mark Stoneman nicked Michael Hogan's first ball of the day to Nick Selman, who took a neat catch at second slip, and that set the tone for a rare Surrey shocker.
Glamorgan captain Kiran Carlson nearly claimed a stunning catch at mid-on to dismiss Hashim Amla off the bowling of Lukas Carey, but he unfortunately spilled the ball. Carey nonetheless dismissed Ryan Patel, again caught smartly by Selman at slip, and then Amla went too - this time caught behind by Tom Cullen for just four.
Jamie Smith was the next to go, caught by Cullen from Joe Cooke's bowling, leaving Surrey at 35 for 4.
Such a position called for responsible batting, not something Nico Reifer delivered when he smacked Andrew Salter up in the air to be caught by Rutherford.
Tim David also fell to Salter - Selman again the catcher - as Surrey slipped to 63 for 6.
Salter finished with career-best List A figures of 3 for 37 and when Clarke was finally dismissed by Andy Gorvin, Surrey had inched their way to a below-par total.
Veteran Clarke - who will retire at the end of the season after a fine career - was Gorvin's first Glamorgan wicket.
Carey finished with 2 for 28 and the outstanding Hogan 1 for just 18 runs from his 10 overs.
Rutherford struck two superb boundaries through cover in the same Matt Dunn over at the start of Glamorgan's reply, but the Surrey quick did bowl Selman for six. Rutherford's calm batting - it was particularly pleasant to watch his off-side strokes - took Glamorgan to 52 for 1 after 10 overs.
New Zealand's Rutherford reached 50 off just 45 balls with 10 fours as he and Steven Reingold, who scored 40, put Glamorgan in complete control.
Rutherford slog swept Dan Moriarty for six into the Sophia Gardens stands to bring up the 100 and although he was caught next ball, he had already done the hard work.
Billy Root was dismissed for 18 with Glamorgan within one run of victory, but Cullen finished the job with 23.1 overs still to be bowled of the home side's second innings.