Teaming up with Ajay Kumar (36), they produced a fifth-wicket partnership of 110 runs that seemed to have sealed the win for HSOB.
Shortly before the wicket-taking exploits of Loffler and Vyas, OBR looked as if they would see some respite after a big appeal for a stumping, but the decision was not out.
Despite thinking they had got their man and made a breakthrough, OBR rallied and were able to force Castle out to the crease, sporting a suspected groin tear after he fell awkwardly in the field.
HSOB technically had a man to spare, but the speed at which the wickets fell meant they could not be found in time when Loffler took his team's eighth wicket.
A game that had been a near-certainty now hung on a knife's edge for the next four balls as Castle saw out the last ball of the over before Marshall Norris hit a boundary to win the game and save Castle from running.
With the bat, OBR came out strong, but ultimately struggled to make meaningful partnerships that would have set a more challenging total.
Josh Adams was the star of the innings; his 54 runs coming as the two OBR openers struggled to find runs, Paul Stewart earning just two from 33 deliveries.
The opening HSOB bowling attack of Marshall Norris (0-33 off six overs) and Cody Andrews (2-39 off six) constricted the start of the innings, but Adams was able to find gaps and keep the scoreboard moving.
Aided by Nick Greeks (30) and Ian Loffler (31) through the middle of the innings, 164 after 37 overs seemed like a par score.
HSOB's bowling attack had seen six wicket-takers, with the pitch looking to favour the team with the ball.
OBR captain Greeks said Adams and Stewart kept the scoreboard ticking over early, setting a good foundation for the latter part of the innings.
“I was very happy with how everyone chipped in. Again, though, not batting our 40 overs kept us 20 to 30 runs short of what we thought was a winning total.”
Two early catches in the HSOB innings could have made the difference in what he said was “another good battle”.
“Baxter's century was constructed, and he played exceptionally well through his whole innings, proving the difference at the end of the day.”
HSOB captain Carl Shaw said he was proud of how they were able to fight back after OBR had made a “really good start” through Adams.
“Jagroop (Singh) led the way again, showing beautifully how good line and length builds pressure and leads to wickets.
“Unfortunately for Jagroop it's hard not to give the best performance to Baxter and his brilliant century.
“There were wonderful shots the whole way through, all around the ground. It was (a) really well crafted (innings).
“OBR never ever give up, which was why they made the final few overs so exciting. Building the pressure . . . right till the last run, and they had the chance of winning.”
■ See the GBHS-Horouta report .