Bristol are a point clear of second-placed Leicester with more than half the Premiership campaign over, and head coach Richard Hill said: "It's unbelievable. We seem to scrap these wins out.
"If you take away the Leicester match (Bristol lost 43-15 three days before Christmas), we've not conceded a try in our last five games, which is where our success has come. It has been a big defensive effort."
Sale, whose hopes of successfully defending their title are disappearing under the weight of numerous injury blows, saw both props Lionel Faure and Stuart Turner fail to last the distance after they suffered neck problems.
Leicester, meanwhile stayed firmly in the title play-off zone by ending Saracens' resurgence with a 28-15 Welford Road success, but fellow challengers Wasps came unstuck at Bath, losing 30-19 after the home side's New Zealand wing Joe Maddock scored two tries.
Wasps wiped out a 13-point deficit to lead 16-13, and rugby director Ian McGeechan conceded: "We got into a winning position, but we blew it tactically."
Skipper Lawrence Dallaglio had already been substituted by the time Bath staged their late recovery, and another largely ineffective performance suggests an England recall for the 2003 World Cup winner is unlikely.
At the Premiership basement, bottom club Worcester's priceless 10-9 victory over Franklin's Gardens hosts Northampton left them just six points behind Saints.
Worcester rugby director John Brain said: "There is lots of character in this team. We are still a team, we are still together and we are still capable of beating anyone.
"If we had lost (against Northampton), it would have been a disaster. But we are still in touch, and we've still got a chance."
Elsewhere, Newcastle rugby director John Fletcher offered a realistic appraisal after the Falcons collapsed 43-15 against Harlequins, for whom highly-rated England sevens ace David Strettle scored three tries.
Newcastle are 10th, one point above Northampton, and Fletcher said: "We are dragged into it.
"One of five teams will go down, and there will be a good side relegated this season. Harlequins were better than us in just about every area."
And Gloucester moved back into third spot above Wasps, courtesy of a 15-3 Kingsholm success against London Irish after tries from Olly Morgan and Iain Balshaw stalled the Exiles' impressive Premiership winning run.
Irish rugby director Brian Smith though, was left distinctly unimpressed by a playing surface that made life difficult for both teams.
Smith said: "The pitch was rubbish. It is a shame we have to play on surfaces like that - it just wasn't up to standard, and Dean Ryan (Gloucester coach) said the same."