Celtic gained further separation from second-place Motherwell despite being held to a 1-1 draw by St. Johnstone at McDiarmid Park on Tuesday.
The Hoops took the lead in Tuesday's Premier League affair thanks Efe Ambrose in the 37th minute, but his strike was canceled out eight minutes from time when Nigel Hasselbaink equalized for St. Johnstone.
Also on Tuesday, Motherwell was on the wrong end of a 1-0 result at Fir Park as Johnny Russell handed Dundee United the victory with the lone goal in the 17th minute.
Celtic improves to 59 points on the season to move 19 points clear of second- place Motherwell, which does hold a game in hand over the Hoops.
St. Johnstone remains on 37 points while Dundee United improves to 36 points.