The 45-year-old has been in charge of first-team affairs at the club since John Mitchell departed in December, with Diamond overseeing four straight wins in all competitions.
"For the next couple of years, the coaching team will be staying as it is," he told BBC Sport.
"We're still bottom of the league, but to beat the side that's only a couple of places above us was really important. But this week we come across the top of the league, which is a completely different proposition.
"We've got to be at the top of our game and they've got to have a shocker, driving up in the fog and the ice, for us to stand a chance of winning."
Sale were 26-25 winners over London Welsh on Sunday.