Jerome scored a cracking long-distance effort at Anfield while Benitez added a second from close range - his first for the club.
McLeish believes the goals will have given them a massive confidence boost and that they will improve the more they lead the line together.
"They've been a handful but I think there's more to come from them," he told the club's official website. "They obviously gave themselves a big shot in the arm the other night by scoring a goal each - their first of the season.
"Although they're paid to score goals, that's got to have done their confidence the world of good.
"Cameron is looking very hot in training and long may he keep that confidence.
"But he also needs to keep working at the technical side of his game."