With wet conditions hampering any chance of an open and flowing game both sides deserve credit for producing a game which kept a large crowd entertained.
After Thatto edged a closely fought league encounter earlier on in the season the game was always going to be a close run thing and so it proved.
Leigh got the better of the opening exchanges and some strong defence got them into a position that allowed centre Tom Worthington to slide over in the corner for a try that he improved himself.
Stung into action Thatto slowly hauled their way back into the contest and on the back of a good kicking game from half-backs Jack Jones and Tom Rigby then hit back as Dave Meadows crossed.
Both sides were producing some aggressive defence and added to the slippery conditions this meant the error count was always going to be high.
Worthington extended the Leigh advantage when he grabbed his second touchdown in the 23rd minute, however, once he had tagged on his second goal that proved to be the end of his sides scoring.
Just three minutes later James Tracey ran a great line to burst over from 20 metres to make it 12-10 at the break and after a compelling first half the players returned to the dressing rooms.
A 48th minute penalty from Jones levelled matters and just seven minutes later man-of-the-match Leon Tatlock collected a superb inside pass from Jones to force his way over for a try that gave Thatto the lead for the first time.
Despite missing with the conversion Jones added a second penalty to make it 18-12 with just three minutes remaining, and despite Leigh desperately trying to get back into the contest several handling errors let them down.
With just seconds left Thatto sealed their win when a great handling move on the last tackle saw Meadows dive over in the corner and with the last kick of the match Jones added the touchline conversion.
“We kept to our game plan and I thought out kicking game was very good,” said a delighted Thatto head coach Jimmy Waterworth.
“Our forwards were very good but they had to be, Leigh just kept going and going and really tested us.
“Our target now is to make the Grand Final and then hopefully we can re-claim our title.”
Leigh East head coach Danny Kilshaw was also able to take something out of the contest.
“I think their experience was crucial in the end,” he said.
“We could maybe have snatched it at the end but probably suffered from a lack of composure.
“We’ll now look to concentrate on the league and target getting to the Grand Final.”