Off-spinner Xavier Falconer (2-5 from two overs) and seamer Pakawa Moldon (2-15 from three) were the pick of Johnsonville's attack.
The Bay's Cameron Walters (1-7 from two overs), leader of the Bay's pace attack, gave his team the best possible start, with the wicket of Johnsonville No.2 Joshua Stephen three balls into the innings (5-1).
The Wellingtonians' first-drop, Blake Taylor, played a match-winning hand — 37 off 60 balls, with four boundaries, in 71 minutes — before he was bowled by Gayesha Mahabalage (1-9 from two overs) off the first ball of the 19th over.
Manjot Singh (1-5 from two overs) had earlier had Stephen's opening partner Max Charles (11) out, hit wicket, to end the 11th over.
The Bay's Oliver Mackintosh (1-1 from 1.2 overs) took the only other wicket to fall, that of No.5 Conor Rook (2) one ball into the 22nd over, to reduce Johnsonville to 90-4. They made 97 in 23.2 overs.
Johnsonville coach Geoff Charles was impressed by Reynolds, with the bat, and the Bay overall.
“Jonah looked the goods and has excellent technique,” Charles said.
“Poverty Bay showed stickability yesterday and if they take their catches, they'll win games.”
This morning the Bay were to play Hutt Districts Blue and this afternoon, on the same Marewa Park No.1 artificial pitch, they were to face Karori Black in their third game of the four-day tournament.