Two second-half goals gave Mansfield their first league win in seven games and ended Kettering's recent good run.
Home goalkeeper Kelvin Jack produced a fine save from Simon Grand's header in the best chance of the first half.
But Jack later diverted the ball into his own net as he failed to deal with Adam Smith's high cross into the box.
Kettering, undefeated in seven league matches, pushed forward, but Louis Briscoe sealed the win when he gathered Paul Connor's pass and shot past Jack.
Kettering manager Marcus Law tells BBC Radio Northampton: "To lose points at home is always a disappointment. We felt we were in control of the game until the (goalkeeping) mistake, and I'm disappointed we didn't have enough character to roll our sleeves up and try to get something out of it.
"We ended up plodding through the second-half. It's becoming a common trait that we only turn up for 45 minutes at home.
"It's something psychological and we need to address it."
Mansfield Town assistant manager Duncan Russell told BBC Radio Nottingham:
"I'm delighted. We knew how important it would be too roll our sleeves up and battle and we did just that.
"In the first half they had the better of the play but in the second half we opened them up and deserved the win."
Kettering: Jack, Dempster, Roper, Graham (Furlong 57), Davis, Solkhon, Noubissie (Boucaud 65), Green, Dance, Marna, Kelly (Makofo 62). Subs Not Used: Cooper, Pryor.
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