In-form Hoops midfielder Commons drove past Caley keeper Dean Brill after two minutes for his 15th goal of the season but the Hoops failed to capitalise on that in the first half as the home side grew in confidence at the Tulloch Caledonian Stadium.
Commons saw a chip clip the bar after the break but although the visitors could not find top gear, they did enough to stretch their unbeaten run in the league to 18 games.
James McFadden scored his first Scottish Premiership goal of the season as Motherwell consolidated second place with an emphatic 5-1 victory at Partick.
Former Motherwell winger Steven Lawless opened the scoring but any hope Thistle had of claiming their first Premiership win at Firhill was extinguished before an end-to-end first half finished.
Keith Lasley quickly equalised before Zaine Francis-Angol scored an excellent solo goal and McFadden lobbed home before the break.
Lionel Ainsworth and substitute John Sutton added to the scoring to seal a big win for Stuart McCall's side.
Paul Cairney inspired Hibernian to a 3-0 win over Kilmarnock to give manager Terry Butcher his first victory at Easter Road since joining the club.
Midfielder Cairney set up Paul Hanlon to head home from a corner in the first half before sealing the points with a fine strike after the break.
Lewis Stevenson added gloss to a fully deserved win with a fierce effort from distance in injury time.
Stevie May's first Scottish Premiership hat-trick took his tally for the season to 15 as St Johnstone beat a make-shift Dundee United side 3-0 in Perth.
Arabs boss Jackie McNamara made eight changes to the side humbled by St Mirren on Boxing Day but the move back-fired as the McDiarmid men claimed three a 3-0 win.
May put the hosts ahead first from the penalty spot after United defender Calum Butcher had been shown a straight red for a last-man barge on the Scotland Under-21 international.
His successful spot-kick ended his team's 460-minute wait for a goal and he grabbed another with a terrific strike from a ridiculously tight angle on 57 minutes before tapping in a third with two minutes left.
Hearts ended a five-match losing streak after mounting a second-half comeback to claim a 1-1 draw against St Mirren in Paisley.
The Scottish Premiership's bottom side looked set for another difficult afternoon after finding themselves trailing to Steven Thompson's opener within a couple of minutes of kick-off.
But the Jambos showed a positive response to a 4-0 drubbing against Kilmarnock in their last outing when Jamie Hamill's equaliser ensured they would not return to Edinburgh empty-handed.
Nicky Low's free-kick in the second minute at Pittodrie proved decisive as Aberdeen took a 1-0 win against second-bottom Ross County.
The Dons dominated large periods of the game but Low's goal was enough for the three points.