The former Sri Lanka Captain hit a top score of 59 as SLC Reds overtook SLC Blues total of 146 for seven with six wickets and one over to spare.
The wicket-keeper batsman also went on to complete his second successive fifty from 44 deliveries with the help of six boundaries.
Chandimal also added 54 runs for the second wicket along with Oshada Fernando who made a 23-ball 27 inclusive of three boundaries.
However, it was Asela Gunaratne and Chamika Karunaratne who added the finishing touches for SLC Reds while putting on an unfinished fifth wicket stand of 31 runs in 3.3 overs.
Earlier, Dhananjaya Lakshan struck a fighting half-century to help SLC Blues post a competitive 146 for seven after they were put into bat.
Lakshan, who was promoted to open the batting, hit a 47-ball 55 with the aid of six boundaries and added 56 for the second wicket with Sadeera Samarawickrama.
All-rounder Lahiru Samarakoon then provided some momentum for SLC Blues during the latter stages by smashing an unbeaten 35 from 21 balls studded with one six and four boundaries.
Opening bowler Himesh Ramanayake had splendid figures of four wickets for 31 for SLC Reds.
SLC Blues: 146/7 in 20 overs (Dhananjaya Lakshan 55, Nishan Madushka 25, Lahiru Samarakoon 35 n.o, Chamika Karunaratne 2/37, Himesh Ramanayake 4/31)
SLC Reds: 148/4 in 19 overs (Dinesh Chandimal 59, Oshada Fernando 27). (C.D)