Celtic needed a second half penalty from substitute Kris Commons to rescue a point in a 1-1 draw with Motherwell as their stuttering start to the season continued.

The champions dominated early possession but it was Motherwell who took a 19th minute lead when John Sutton volleyed home Josh Law's cross from close range.

The English striker should have had another minutes later but somehow sliced his effort wide from four yards out.

Ronny Deila had handed a host of first team stars a rest following their Europa League exertions away to Salzburg on Thursday but brought captain Scott Brown and Commons off the bench at the break.

The pair combined to haul Celtic back on level terms as Brown won a 68th minute penalty that Commons converted.

Celtic continued to push for a winner but a series of saves by Motherwell keeper Dan Twardzik earned his side a point that leaves Celtic in fourth place, five points behind leaders Dundee United who thrashed rivals Dundee 4-1 earlier on Sunday.

It was not the 39th birthday present Deila would have wanted and leaves him with just five wins from his first 13 matches in charge of the Scottish champions.

Celtic had penned Motherwell in their own half early on but failed to cause the Steelmen's defence any problems and it was Motherwell who opened the scoring in the 19th minute following a rare foray forward.

Sutton started and finished the move as he laid the ball off to Law whose low cross found the striker in the six-yard box where he volleyed past Lukasz Zaluska.

Sutton somehow missed a golden chance to fire his side two in front in the 27th minute. Keith Lasley's cross found the striker unmarked but the Englishman managed to slice his effort wide from four yards out.

Beram Kayal was inches away from hauling Celtic level when he sent a low shot curling round the post before Twardzik made a superb save to keep out a Virgil van Dijk header from close range.

Commons, along with club captain Brown, came off the bench for the second half and he almost made an instant impact when he forced Twardzik into a good save to stop his low drive.

The Motherwell keeper then denied Callum McGregor as he pushed away a fierce strike from the midfielder before on-loan Manchester City striker John Guidetti fired an Emilio Izaguirre cross into the side netting.

Celtic were containing Motherwell in their own half and finally got on level terms thanks a 68th minute penalty from Commons.

Referee Brian Colvin pointed to the spot after Brown's surging run into the box had been abruptly ended by Motherwell defender Craig Reid and Commons converted the spot-kick, drilling his left-footed effort straight down the middle.

Celtic took confidence from the goal and McGregor fired an effort wide before Twardzik pulled off a superb save to stop the midfielder's shot that had taken a wicked deflection.

Elsewhere, Dundee's unbeaten start to the season came to an emphatic end with a 4-1 defeat at home to city rivals United.

Mario Bilate's penalty gave United a 25th minute lead before Ryan Dow doubled their advantage just after the break. Headers from Callum Morris and Keith Watson completed the scoring for United.

Things got worse for the home side when Thomas Konrad was sent off in the 90th minute for a second bookable offence before Greg Stewart scored a consolation goal in the third minute of stoppage time.

However, that wasn't enough to stop United moving to the top of the table on goal difference from Inverness Caledonian Thistle.