Having already secured the series, SA A missed out on a clean sweep as the hosts claimed a six-wicket win in the rain-reduced 47-over contest.
After winning the toss and electing to bat, SA A struggled for momentum.
Fresh from his century in the previous match, Pretorius anchored the innings with 65 off 57 balls, which included five fours and four sixes. Following the early dismissal of Tony de Zorzi for nine, Pretorius and Marques Ackerman (14) added 66 for the second wicket to steady the innings and take the score to 93-1.
READ: Stokes future puts Bazball under pressure
The momentum shifted when Ahmed produced a return catch to dismiss Pretorius. The breakthrough triggered a collapse as SA A lost their remaining eight wickets for just 53 runs.
The England international leg-spinner finished with six for 34, while James Coles provided excellent support with three for 23 as SA A were bowled out for 146 in 31.3 overs.
In reply, Gerald Coetzee (2-35) struck early to remove Ben McKinney (16) before having Ahmed caught for 15, leaving the Lions on 46-2 after 8.1 overs.
Ottneil Baartman (1-31) then accounted for captain James Rew (19), who edged to first slip where Prenelan Subrayen held a sharp catch. Rain interrupted play with the hosts needing a further 84 runs for victory with seven wickets in hand.
ALSO: Proteas climb to second in WTC standings
After the resumption, Asa Tribe (8) feathered Nqaba Peter (1-38) behind to the wicketkeeper, but the Lions continued steadily towards their target. Coles struck an unbeaten 63 off 58 balls, which included seven fours and two sixes, while Ben Mayes finished 17 not out as the hosts sealed victory with 21.5 overs to spare.
Despite the defeat, Wandile Gwavu’s side can reflect on a successful tour, having swept the four-day series 2-0 and claimed the one-day series 2-1.
Photo: Gareth Copley/Getty Images