They travelled up the M1 to Leicester Vipers, a ground where they traditionally struggle, and so it proved again.
Shorn of several influential players, handling errors and the committed defence of the home side prevented Tows from putting a pattern to their game.
A penalty to the hosts after 25 minutes put Tows further on the back foot, as did their perennial bad habit of upsetting the referee.
Finally, Tows put together a move for Matt Bodily to cross and James Falvey landed the conversion to turn round 3-7 up at half time.
Playing with his usual flair and spirit, Tows flanker Eugene Baxter opened the scoring in the second half with a try under the posts.
Falvey added the extra points to stretch the Tows lead to 3-14.
But Vipers hit back with an unconverted score from a line out drive and excellent cover defence kept Tows pegged within six points.
James Tilley eventually muscled over in the corner however to hand Tows a more comfortable 11 point margin.
The pack refused to bow to pressure at the death to secure Tows another win in their unbeaten League campaign.
Tows will need to rekindle their previously glittering form this week. They have a Lewis Shield game against ONs at Northampton School for Boys on Tuesday night (KO 7.30pm) and a tough League game at Bugbrooke on Saturday (KO 3pm).