In their second away match in succession, Lewes yet again came up close with Crowborough winning this see-saw of a match in the last few minutes to snatch victory from a spirited Lewes outfit, who once more came away with two losing points.
The first few minutes of this hard-fought encounter were closely matched but it was the visitors who opened the scoring on five minutes with a well-taken penalty from outside-half Joe Terry to make it 0-3.
It took Crowborough only five minutes to equalize at 3-3 , winning a penalty after a line-out which their outside-half, Sam Kinslee, slotted over.
On the quarter-hour Lewes scored the first try of the match following a fine spell of attacking rugby, ending with scrum-half Sam Hewitt crashing over, Terry adding the extras, to see Lewes go ahead at 3-0.
Just on the half-hour, Crowborough hit back at 8-10 , their hooker Alex Purnell scoring an unconverted try from wide out, and, straight from the re-start, a mistake by Lewes gifted the ball to their opponents, enabling flanker Josh Grewcock to touch down for a try, converted by Kinslee, to take the lead for the first time at 15 - 10.
Crowborough's heavier pack were now beginning to dominate the rucks and mauls, giving their side more possession than earlier, and this resulted in another, unconverted, try three minutes later from No. 11 Conor Hand out wide on the right to stretch further ahead at 20-10, which remained the position at the half-time whistle.
Lewes started the second half brightly, going straight onto the attack with another flowing move which was rounded-off by second-row Nathan Lowen with a try near the posts, Terry converting, to draw nearer at 20-17.
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Crowborough responded after 50 minutes with another penalty from Kinslee to pull away at 23- 7, only for Lewes to re-take the lead 23-24 with Lowen's second try under the posts, Terry adding the extras.
After 62 minutes, the Lewes pack won the ball inside Crowborough's 22 metre zone before feeding the ball out right for speedy winger Billy Shiell to score his side's fourth, bonus-point, try under the posts which Terry duly converted, to go further ahead at 23 - 31.
But with an increasingly high penalty count against Lewes and, willed on by the large home crowd, Crowborough were able to up their game, narrowing the points difference to 28-31 minutes later with an unconverted try wide out left by centre Gary Stevens.
The last minutes of this pulsating encounter saw Lewes striving to hold onto their slender lead, managing to thwart wave after wave of Crowborough attacks by their resilient tackling and unforced errors from the home side.
But the unrelenting pressure finally told seconds from time as the host's No. 8, Freddie Purnell, scored a push-over try from a few metres out, converted by Kinslee, to see Crowborough secure the bonus-point win by 35 - 31.
Another close but disappointing defeat for Lewes who hope the return of several stalwarts for their home game at the Stanley Turner Ground on Saturday - against second-placed Kent side, Vigo, will reap them greater rewards. Kick off is at 3pm.
Lewes: Bocha, Moule, Becker, Lowen, Cowling, Blunt, Furse (Capt.), Robinson, Hewitt, Terry, W.Shiell, H.Shiell, Feltham, Taylor, Bredin (Reps. all used: Gorbell, Mills-Ward, Nichols).
Lewes 2nd XV made the long trip to Rye, returning with a losing bonus-point after going down 17-10, their points coming via a try from veteran Simon Sampson, converted by Dan Billin, who also slotted over a penalty.