Celtic retained their seven-point lead at the top of the Scottish Premiership with an easy 2-0 win over 10-man Partick at Parkhead. The home side laid siege to the Thistle defence at the start of the match but had to rely on a Kris Commons penalty a minute before the break to give them the interval lead. Thistle midfielder James Craigen had been shown a straight red card by referee Willie Collum for a 'last man' foul on Hoops midfielder Stuart Armstrong to concede the spot-kick. leaving the visitors a player down for the second half. Stuart Armstrong is brought down by Partick Thistle's James Craigen leading to a penalty . Referee Willie Collum shows Craigen a read card for his 'last man' challenge on Armstrong . Celtic striker Kris Commons steps up to convert the penalty to give his side a 1-0 lead before the break . Commons (right) races away to celebrates his 45th minute penalty strike . Midfielder Stefan Johansen, stand-in skipper in the absence of suspended Scott Brown, added a second in the 63rd minute as the encounter turned into a Hoops procession. With second-placed Aberdeen beating Inverness 1-0, Ronny Deila's side maintained the gap over the Dons but also have a game in hand as the title race draws closer to conclusion. With a heavy schedule in mind, the Hoops boss returned midfielder Nir Bitton, Gary Mackay-Steven and striker John Guidetti his starting line-up. Thistle manager Alan Archibald was forced into one change with forward Kallum Higginbotham coming in for the injured Kris Doolan but he was mostly a spectator as the Firhill defence was forced to withstand an early Hoops' barrage. Celtic came close twice before two minutes had elapsed. Stefan Johansen doubles Celtic's advantage in the 63rd minute with left-footed shot into the bottom corner . Johansen is mobbed by his team-mates following his second-half strike . Parkhead defender Virgil van Dijk, up for a corner, flicked an Armstrong cross against the crossbar at the near post before a desperate blocking tackle by Maryhill defender Conrad Balatoni prevented an almost certain goal from Johansen's drive. Balatoni again came to Thistle rescue in the ninth minute, beating Guidetti to a header in front of an empty goal, after left-back Emilio Izaguirre had troubled Fox after surging into the penalty area. Moments later, Mackay-Steven was set up Johansen but his goalbound drive from 12 yards was deflected away by Thistle defender Callum Booth. Yet, in the 21st minute, in a rare attack, the visitors almost snatched the lead but Higginbotham's spectacular volley from 14 yards was saved by Craig Gordon - but only on the stretch. Commons' long-distance drive in the 28th minute just cleared the bar but a minute before the break he was more accurate from the spot, firing the penalty low into the corner giving the despairing Fox no chance. Leigh Griffiths spurns a glorious opportunity to put Celtic 3-0 ahead late in the match . The goal came as some relief to the home fans who had grown slightly irritated as the first half wore on. Two minutes after the break Commons forced Fox into a decent save with a powerful 25-yard drive and while the Maryhill defence cleared their lines from rebound it looked ominous. Thistle continued to defend stoutly and desperately in equal measures but were undone again when Johansen took a clever Guidetti pass before rolling the ball into the corner of the net from 10 yards. Two minutes after replacing Guidetti, Leigh Griffiths somehow turned a Mackay-Steven cross past the far post from two yards out but it was inconsequential. In the 79th minute, with the game drifting, Gordon made another good save, this time from Thistle substitute Gary Fraser, on for Stuart Bannigan. Johansen came close at the other end with a chip which Fox tipped over the bar, after the Norwegian had weaved his way through the Jags defence.
Kris Commons fired Celtic into the lead on the stroke of half-time .
Partick Thistle's James Craigen was sent off before the penalty .
Stefan Johansen doubled the home side's advantage in the 63rd minute .