Celtic the Scottish Premier League championship title following a comfortable home victory against Inverness Caledonian Thistle.
Joe Ledley's right-footed drive in the 66th minute was sandwiched by a Gary Hooper double strike, the Englishman sparking a lacklustre match to life.
Substitute Georgios Samaras thundered a fourth off the underside of the crossbar.
Aaron Doran's late strike was scant consolation as the party commenced.
However, Celtic's 72-point tally includes six draws and six defeats, four of which were suffered on the road, and the club is now on course for its lowest season haul under the Northern Irishman, having finished the 2010-11 season in second place with 92 points.
A glancing header from Caley midfielder Owain Tudur-Jones inched past the Celtic post in the only first-half effort from the visitors.
Anthony Stokes had the ball in the back of the net shortly after the half-hour mark, but the assistant referee had already flagged him offside.
After a goalless first half, Emilio Izaguirre replaced the injured James Forrest for the restart as a similar pattern to the match continued: a free header for Efe Ambrose from six yards out clearing the Caley Thistle crossbar.
The stalemate was finally broken when Hooper found the net with a cool finish, picking up a threaded pass from Commons on the edge of the penalty area and slotting low past Antonio Reguero.
Five minutes later, captain Ledley calmly collected a square ball from Mikael Lustig and fired right-footed low into the bottom corner to give the home support confidence of a party.
Celtic slipped into cruise-control and added a third when Commons swept down the left wing and slotted a ball across for Hooper to casually flick between his legs and over the line from six yards.
Samaras and Paddy McCourt both made late appearances as Celtic aimed to finish the match with a semblance of style, and the Greece international delivered a rousing finish with a fine solo effort.
Capitalising on a Tudur-Jones blunder, Samaras drifted unchallenged into the Caley Thistle penalty area and crashed a shot in off the underside of the crossbar.
Doran hit a casual effort past Forster after good work from Richie Foran in injury time but Celtic's fans were already set to party.