The hosts, precariously poised at 24 for three overnight, were eventually bowled out for 239 in reply to Guyana’s competitive first day total of 271.
Corbin, a 19-year-old right-hander, struck a career-best 74 while left-hander Reifer, nearly double his partner’s age, contributed 57 to revive the hosts after they slipped to 28 for four early in the day.
The pair added 107 for the fifth wicket but Guyana, on the back of three wickets from pacer Brandon Bess (3-38) and Veerasammy Permaul (3-75) and two from Esuan Crandon (2-75), held their nerve to earn a slim lead.
Captain Sewnarine Chattergoon struck an unbeaten 28 and Christopher Barnwell added 23 not out to stretch Guyana’s advantage to 92 as they closed on 60 for one.
CCC lost Kjorn Ottley (9) inside the first 10 minutes as he popped a catch to short leg off Permaul.
But Corbin and Reifer dropped anchor after that to bring their side back into the contest. Both batsmen reached fifty just before taking lunch at 121 for four.
Corbin, stylish in attack and defence, reached his landmark off 102 balls with six fours. Reifer soon followed, with his ninth boundary, off 83 deliveries.
Esuan Crandon’s medium pace earned the breakthrough after lunch when he earned an lbw verdict against Reifer at 135 for five.
