Sheridan ran on to instant passes from strike partner Francisco Sandaza in each half before applying composed finishes to take Saints level on 12 points with Hearts in the top six of the SPL.
The Irishman has been overshadowed by Sandaza, who has six goals this season, since returning to the club on loan from CSKA Sofia, but McInnes has been delighted with his effort.
The St Johnstone manager said: "Big Fran has been getting a lot of plaudits and rightly so, he brings a swagger and an ability to us at the top end of the pitch, but he will be the first to acknowledge, and we recognise, how hard Cillian has been working. He occupies defenders.
"Potentially it's a decent two to work with - both have presence, both have the ability to score goals and both have pace.
"Cillian is very quick off the mark, times his runs well and finishes.
"The beauty with Cillian, and possibly why we persevered with him when he wasn't scoring goals, we have worked with him before.
"It took him a wee while to get going the last time but once he did he went on a good run of goals and we're hoping he will do that again."
The opener came on the half-hour mark amid a spell of home pressure following a tight opening quarter and Hearts struggled to break Saints down afterwards.
"The first goal is very important in any game and once we get that I think there was an element of control to what we were doing," McInnes said.
"Hearts played in and around us but never got through us at any time.
"We restricted them to very few opportunities and we stopped their better players having an effect, which is very important when you come up against a better side.
"I think Hearts will be the third team in the SPL team this season so it's no mean feat to beat them. I thought the team were excellent.
"We were clinical at one end and dogged, resilient and hard-working throughout."
Hearts manager Paulo Sergio admitted his team's defending was a concern after Sheridan first ran in behind their high back line and then straight through the middle for the second.
Sergio said: "When the game starts you can see Hearts controlling the game and trying to play and we were defending well their kind of game - long balls in behind us and to the big guys up front.
"I think we should do better in the first half with the ball, we missed some movement up front, but second half we were moving the ball better, but we made a second mistake.
"Our goalkeeper doesn't make a save all the game and picked out two goals with things we are giving to our opponents.
"It's not the first time and that worries me a lot. You can't win games by giving away goals like we are giving to our opponents.
"We are giving the confidence to our opponents and we have to stop that."
Sergio took Andy Webster off at half-time and put Adrian Mrowiec back to central defence.
"I didn't find he was very well in the game," Sergio said.
"I put Adrian in that position to have a more technical midfield. It was just tactical."
Source: Team Talk
Source: Team Talk