|Bath (10) 13|
|Tries: Woodburn Cons: Homer Pens: Homer 2|
|Northampton Saints (12) 21|
|Tries: Wilson, Haywood Cons: Myler Pens: Myler 3|
Northampton moved nine points clear at the top of the Premiership with victory over second-placed Bath.
Olly Woodburn's early try and Tom Homer's double from the tee set Bath on their way.
But the visitors responded through James Wilson and Mike Haywood to go in 12-10 ahead at the break.
Stephen Myler kicked three second-half penalties, while Homer could only reply with one, as Saints inflicted a first home league defeat on Bath this term.
It was also a second successive loss in the Premiership for Mike Ford's men, who were undone by Saracens last weekend, and their four-year wait for a home win over Saints continues.
The hosts made an explosive start to proceedings and crossed the whitewash within two minutes, albeit in a scrappy manner.
A last-ditch Jamie Elliott tackle denied Semesa Rokoduguni on the right, but the hosts kept possession and Homer fed a wayward pass to Woodburn, who steadied himself and tentatively touched down, with the try eventually awarded by the television match official.
Full-back Homer, making his home debut after his switch from London Irish, was on kicking duties and landed the conversion before slotting a penalty.
Bath's defence held strong for half an hour but a period of sustained Saints pressure saw Elliott break forward and Wilson was sent over in the corner, although Myler missed the extras.
Northampton went ahead when they stole a Bath line-out and a sweeping left-to-right move ended with hooker Haywood thundering over, with Myler adding the conversion.
Homer could have reinstated his side's lead just before half-time, but he missed with a penalty.
A moment of petulance from England centre Rokoduguni, in which he threw the ball away after it had gone into touch, gave Saints a penalty after the break and Myler duly converted, before adding his second penalty of the afternoon.
Homer brought Bath back to within five points of the champions with a short-range penalty, after Saints failed to roll away at the ruck, but Myler cancelled it out with his third.
George Pisi left Saints a man down for the last 10 minutes, after he was sin-binned for a mid-air tackle on Rokoduguni, and although Bath pushed forward they were unable to make it count.
Bath head coach Mike Ford: "They are a very experienced side, and their tactics were very good. They strangled the life out of us in the second half.
"In the second half, the basics let us down, but their basics were very good.
"I think it showed today why they are the champions and why we probably didn't get into the top four last season.
Northampton boss Jim Mallinder: "It is a nice cushion, but if we lose next week against Harlequins then it negates today's good win.
"We are very pleased. It is a good position to be in.
"We played well in the first half after a poor start. We had tempo and width and scored two good tries, then in the second half our defence won us the game.
"It is one of our best performances of the season."
Bath: Homer; Rokoduguni, Burgess, Eastmond, Woodburn; Devoto, Young; James, Webber, Thomas, Hooper (capt), Day, Garvey, Louw, Fearns.
Replacements: Batty, Auterac, Palma-Newport, Faosiliva, Houston, Stringer, Jennings, Arscott.
Northampton: Wilson; K Pisi, G Pisi, Stephenson, Elliott; Myler, Dickson (capt); Waller, Haywood, Denman, Craig, Day, Manoa, Clark, Dickinson.
Replacements: Williams, Corbisiero, Mercey, Harrison, Dowson, Fotuali'i, Olver, Tuala.