Inverness led 1-0 at the interval courtesy of a Nick Ross penalty in the 45th minute, but up until then had struggled to break down the visitors.
A power cut at one of the city's major substations plunged the stadium into darkness during the interval, but after a delay of around 35 minutes, the second half eventually started.
And it was Caley Thistle who emerged the happier that the lights came back on as Billy McKay goals in the 71st and 88th minutes were added to by Aaron Doran's spot-kick in injury time after Scott Taggart was shown red for hauling down Torbjorn Agdestein as he ran through on goal.
For Shearer, who hopes this will be his last game in temporary charge of Caley Thistle as they look set to appoint a new manager next week, it was a far more pleasing display from Inverness in the second half.
He said: "I was delighted with the second half. It was the first time that I gave them a wee bit of a roasting at half-time.
"We got the break just on half-time with the penalty to go 1-0 up so that settled us down a wee bit.
"I was a bit concerned with the amount of time during the interval before the lights came back on, but we started really well in the second half.
"I think they were more annoyed with themselves as I didn't have to do too much.
"They were annoyed they hadn't reached the standards they are used to because they are very demanding of each other, so I felt we had a really good second half."
- Sports & Recreation
- Caley Thistle