Teenage spinners Ali Jahangir and Callum Bethel took seven wickets between them as they ripped through Hull's batting line-up to give Barnsley CC their first win of the season.
Hosts Hull were skittled for 129 chasing 184 as Barnsley, who are playing a lot of youngsters this season after a mass exodus of star players, gained a confidence-boosting victory.
"It was crucial to get the first win on the board," said Steven Nuttall, who enjoyed his maiden success as captain.
"We are an inexperienced team so if we had gone five or six games into the season without winning it could have been very damaging for our confidence. We were about 20 runs light of what I wanted with the bat but the pitch was very dry and deteriorated in the second half of the game.
"Sometimes spinners can panic when the conditions are in their favour but Ali and Callum kept calm and won us the game. They were excellent."
Jahangir started off nervously after he conceded 72 runs off 11 overs in the season opener at Driffield seven days earlier but soon found his rhythm and took four wickets for 37 which made him the club's top wicket-taker this season. Bethel was playing for the first time this year and produced a fine display to take three for 22 off nine overs.
Hull's openers reached 47 in the first nine overs but, after Barnsley seamers Callum Millward and Harry Rouse made the initial breakthroughs and veteran Gary Nuttall bowled three overs, the spinners took over. Hull lost regular wickets and reached 100 with five down then lost three more without adding any runs. The hosts' tenth-wicket pair added 25 runs but Jahangir and Bethel removed the final two batsmen within five balls.
Earlier in the match, Barnsley opener Matt Wilson (52) made it two half-centuries from as many innings this season and Tom Shaw batted well before being run out three runs short of a 50.
