After winning the toss and electing to bat, Blues captain Katich scored 53 off 41 balls to lead his team to 144 for six. In reply, the Eagles struggled to 91 for nine with seamer Clark capturing three for 12 off four overs.
On a flat pitch which offered very little bounce Katich and David Warner (23) shared in a 79-run second-wicket partnership before Warner was bowled by medium-pacer Ryan Bailey with New South Wales on 82 for two in the 13th over.
Bailey bowled a superb spell that saw him capture one for ten off three overs.
Katich was next to fall, caught at long-off by Rilee Rossouw off the bowling of seamer Shadley van Schalkwyk, with the 34-year-old Katich’s innings including six fours and two sixes.
The Blues’ innings received some late impetus from the right-handed Moises Henriques, who belted 27 runs off 19 balls with three sixes, while the left-handed Ben Rohrer ended not out on 22 off 15 balls.
Van Schalkwyk was the Eagles’ leading wicket-taker as he captured two for 22 off three overs while veteran fast bowler Victor Mpitsang was economical as he snared one for 11 off his three overs.
The Eagles’ innings never got off the ground as the South African side slumped to 36 for six inside ten overs with Clark picking up two of the wickets to fall.
The Free State-based franchise was only saved from complete humiliation thanks to 40 runs off 37 balls from the left-handed Ryan McLaren.
McLaren was the ninth wicket to fall when he was caught at long-off off the bowling of medium-pacer Henriques.
The Eagles’ demise was caused by a mixture of fine bowling, injudicious shot selection and suicidal running between the wickets.
Katich was superb in the field as he was responsible for two run outs while Clark received fine support from Henriques who claimed two for 13 off three overs.
Fast bowler Brett Lee and off spinner Hauritz were extremely economical as each player picked up a wicket while conceding just 14 and 13 runs from their respective four overs.
The Eagles will have to regroup quickly as they play their next match in the tournament against Sussex on Tuesday in Delhi while New South Wales take on Sussex on Sunday at the same venue.
Teams:
Diamond Eagles - Boeta Dippenaar (capt), Morne van Wyk (wk), Rilee Rossouw, Dean Elgar, Adrian McLaren, Ryan McLaren, Ryan Bailey, Dillon du Preez, Shadley van Schalkwyk, Thandi Tshabalala, Victor Mpitsang. New South Wales - David Warner, Philip Hughes, Simon Katich (capt), Daniel Smith (wk), Moises Henriques, Ben Rohrer, Steven Smith, Nathan Hauritz, Brett Lee, Stuart Clark, Doug Bollinger.