Sandercock's side were trailing 18-6 at the break as they struggled to get a foothold in the game against the side second from bottom in Super League. But his words at the break did the trick as Rovers scored 22 unanswered points to take the win.
"Full credit to Salford because they had a great completion rate in the first half," Sandercock said.
"We dropped a lot of ball and full credit to them for their half-time lead. The second half still wasn't great but our defence was really good and I knew if we could stop them from scoring we'd be okay. It was pleasing to get the win.
"Our ball control was less than satisfactory in the first half, and it wasn't up to first grade standard. We needed to address that and we did.
"It was a good defensive display in the second half. We turned the screw well and in the end we did enough to get the win."
Salford coach Brian Noble felt his side let themselves down after turning around at half-time in front. He admitted a couple of his players went away from the game plan which ultimately cost his side.
"We are disappointed that the game slipped away from us," Noble said.
"We contributed to that ourselves but Hull KR took a step up as well. They looked after the ball better in the second half and put us under more pressure.
"We couldn't do the things we were doing in the first half. A couple of individual went away from the game plan because we were playing well and they were getting giddy. The reason we were playing well was because we were playing well as a team. The effort was fantastic on a day as hot as it was."
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