The battle of the League Two's bottom two saw the Mariners go ahead two minutes before half-time when skipper Ryan Bennett's looping header found the top corner from 15 yards after Nick Hegarty's deep free-kick.
Mark Bower levelled in the third minute of first-half stoppage time when he nodded home Tom Craddock's cross and after a scrappy second period, Asa Hall brought the house down by volleying home fellow substitute Ian Henderson's 89th-minute cross to hand Luton a crucial 2-1 victory.
On his reception from the Luton fans, Newell said: "If I had a big ego it would be deflated now but I don't worry about what people think of me, particularly people who don't know me.
"People have been brainwashed. If that's the reaction I deserve then it's water off a duck's back to me.
"I've got broad shoulders and know what I did at Luton and the people who know me know what I did."