Not for the first time this season, the Moles took the lead, only to surrender it in the last 10 minutes and forfeit all three points.
The Moles have lost 14 points from winning positions, an issue that will certainly have to be addressed if they are to compete at the top end of the Hellenic Premier Division table.
Tallentire's men looked to be in the driving seat at half time with a confident display allowing them to take the lead after 23 minutes when Jake Butler's shot was parried and James Suarez was first to react to smash high into the net.
Seb Bowerman, who ran Slimbridge ragged in the opening 45 minutes, and Jos Millar all went close with decent opportunities, as did Butler, but all were denied by the impressive Dave Evans in Slimbridge's goal.
However, the Moles seemed to lose their way in the second half and with only a slender one-goal advantage, it was always going to be difficult to keep Slimbridge out.
The equaliser was eventually conceded by Dan Weait, whose late challenge in the box resulted in a penalty to the home side on 62 minutes.
Weait saved the spot kick but the rebound was turned in by Shaun Bennett to make it 1-1.
Slimbridge's turnaround was complete eight minutes from time when Liam Harding smashed home from close range when another right-wing break was only half cleared.
Ryan Millward tried an acrobatic effort late on, but the Moles were not clinical enough in front of goal and they left Gloucestershire empty-handed.
"We only have ourselves to blame," conceded Tallentire. "It was just individual errors that cost us."
Despite Slimbridge taking four points off the Moles in their two meetings, Tallentire does not believe that tells the whole story.
"In both games, we've been head and shoulders above," he said. "In the first half we were so superior, I really felt we should have been
3-0 up, it would have been
a more realistic scoreline.
"The first goal we conceded knocked us for six, it was such a sloppy goal to concede."
Summing up their recent form, Tallentire added: "When we're on top, we're creating good opportunities but we're not finishing them off.
"We've got to get over that hurdle. The players need to concentrate longer and apply themselves properly.
"There's a fine line between us winning and losing the game and at the moment we're on the wrong side."
He continued: "We've got to cut out the stupid mistakes.
"I know the players inside out and I know they will be chomping at the bit to put it right."
They have the perfect opportunity to get back on track when they host struggling Abingdon Town at Hill Farm Lane on Saturday (3pm ko).
Abingdon are bottom of the league but Tallentire knows his side will have to perform for the 90 minutes in order to
get the result.
Last time the sides met, it was down to a 93rd-minute winner that the Moles won after another dominating display once again threatened to yield the wrong result.
Tallentire admits it's a 'blessing in disguise' that Binfield have no midweek game as it gives them extra time to iron out the deficincies, allowing more focus and intensity for Saturday.