Hoops held by Dundee United

A deflected Paul Hartley goal six minutes after the break - and a controversial decision by referee Charlie Richmond to deny United a penalty when Roy O'Donovan clashed with Gary Caldwell - looked likely to give the champions all three points.

However, in the 79th minute the Spaniard, on as a second-half substitute for Warren Feeney, nipped in at the near post to flick a Craig Conway cross past Hoops keeper Artur Boruc.

United were well worth their point and might have grabbed all three in the closing stages as they went all out for the winner.

However, they will point to the game's most controversial incident in which Richmond refused to award a spot-kick when O'Donovan appeared to be tripped by Celtic defender Caldwell inside the penalty area.

Richmond ignored the claims to the distress of the Tannadice supporters, then almost immediately injured himself by running in to Celtic midfielder Shunsuke Nakamura - and minutes later was substituted by fourth official Iain Brines.

The referee may have been spared by United's equaliser, which came in a second half in stark contrast to a dull first period.

Celtic took the lead in the 51st minute when Hartley netted with the help of a deflection .

Nakamura had time on the ball inside the United box to lay the ball off to the former Hearts midfielder, whose side-footed shot came off Garry Kenneth before nestling in the corner of the net.

But United built up a head of steam and finally got the equaliser when Sandaza nipped in at the near post to direct a cross from Conway, himself on just seconds earlier for Willo Flood, past the helpless Boruc and into the far corner of the net.