Furuhashi at the double as Celtic stay out in front of rivals Rangers
The Japan international took his tally to seven goals in as many games with his skill in being able to play off the shoulder of the last man twice rewarded following prolonged VAR reviews as Celtic won their 11th successive home league game.
Liel Abada had fired Celtic into a 15th-minute lead before Furuhashi was on target either side of the interval.
Substitute David Turnbull completed the scoring four minutes from time with a superb 25-yard strike.
Victory meant Celtic remained nine points clear of arch-Glasgow rivals Rangers after convincingly defeating the only Scottish side to beat them so far this season.
St Mirren, who dropped to seventh, were the last Scottish side to enjoy a domestic win at Parkhead, nearly two years ago.
Rangers clung on to Celtic's coat-tails as Alfredo Morelos scored twice in a come-from-behind 3-2 win away to 10-man Kilmarnock.
Killie defender Chris Stokes had the home faithful cheering at Rugby Park when he opened the scoring just six minutes into the match with a header from a corner.
Colombian striker Morelos, however, equalised midway through the first half.
Ryan Kent struck six minutes after the break before Kilmarnock winger Danny Armstrong was sent off for a second bookable offence following an elbow in the face of left-back Borna Barisic.
It was from a Barisic cross that Morelos headed in his second goal in the 73rd minute but Rangers had to endure a nervous finish after Joe Wright pulled a goal back five minutes from time.
Hearts remained third in the table following a 5-0 rout of Aberdeen that saw the Edinburgh club score four goals in the first half to the delight of their loyal fans at Tynecastle.
Josh Ginnelly scored twice, with Michael Smith and Lawrence Shankland also on target before the interval.
Cammy Devlin made it 5-0 just after the hour-mark as Hearts, now unbeaten in eight games, were left seven points clear of fourth-placed Livingston.
It was a frustrating night for Livingston after their match at home to Dundee United was called off less than 90 minutes before the scheduled kick-off because of a frozen pitch.
