First-half display sparks Celtic to league opening win
They got off to a dream start as Griffiths slammed home a fourth minute penalty after he had been brought down by County captain Andrew Davies.
Celtic 'keeper Craig Gordon was fortunate to escape with only a booking after bringing down Jackson Irvine as the Australian bared down on goal before Johansen added a second for the hosts in the 35th minute.
Ross County proved more of a threat in the second half and, much to their annoyance, decent efforts from Craig Curran and Raffaele De Vita to reduce the deficit were thwarted by Gordon.
It was Celtic's fourth consecutive competitive victory of the new season and gives the Scottish champions a boost as they take a slender 1-0 advantage to Azerbaijan for the second leg of their crucial Champions League qualifier against Qarabag on Wednesday.
Celtic manager Ronny Deila felt his side's midweek European exploits had taken their toll.
"Always you want to play better and today I thought for 60 minutes it was an okay performance but the last 30 minutes were sloppy and messy," he said.
"But it is only two-and-half days since our last game which was a big match with a lot of intensity and you could see some players were tired."
His Ross County counterpart Jim McIntyre was pleased with his side's second half showing.
"Obviously losing an early goal here meant we had to show real character," McIntyre said.
"In the second half we showed more belief and got in good goal-scoring opportunities but we need to take them."
Before kick-off, John Clark, part of the famous Celtic side that won the European Cup in 1967, was given a standing ovation as he unfurled the Championship pennant.
The home supporters had barely taken their seats again before Griffiths fired home the opener from the penalty spot. The Scotland striker was fouled by Davies and dusted himself down to fire his spot-kick under 'keeper Scott Fox.
Unfortunately for Griffiths he picked up a knock in the incident and his involvement was over soon afterwards when he made way for Serbian striker Stefan Scepovic.
Gordon -- who earlier in the week signed a new contract with the champions -- was handed a major reprieve in the 22nd minute when referee Willie Collum only showed him a yellow card for a foul on Irvine.
The Scotland stopper had raced out of his box to meet the onrushing Ross County forward and clipped him as he rounded him to deny Irvine what appeared to be a goal-scoring opportunity.
Gary Mackay-Steven then forced Fox into a good save with a fierce strike inside the box before turning provider for Johansen to make it 2-0.
The nippy winger jinked away from his marker before rolling the ball into the path of the Norwegian midfielder who rifled the ball past Fox.
A rare foray forward by County at the start of the second half saw a good move end with Rocco Quinn firing weakly into the arms of Gordon.
Curran then had his strike stopped by Gordon before Michael Gardyne fired just over the bar as the visitors looked to reduce the deficit.
Gordon came to the rescue for Celtic again when a free-flowing move from County resulted in a fierce shot from substitute De Vita that the keeper brilliantly blocked.
Celtic remained a threat, however, and moments later sub Kris Commons saw his dipping shot narrowly tipped over the bar by Fox.