Dundee United 3 Partick Thistle 1

A first-half hat-trick by Cammy Smith sent Dundee United past Partick and into the Betfred Cup quarter-finals with a 3-1 win at Tannadice.

The 20-year-old attacker, on loan from Aberdeen, took less than half an hour to effectively decide the tie with two composed finishes and a penalty to leave the Ladbrokes Premiership side stunned.

Thistle's Sean Welsh reduced the deficit from the penalty spot in the 64th minute to offer hope of a comeback but Ray McKinnon's Championship side remained mostly in control against a side who had gone into the game full of confidence after winning their first five games of the season.

United came flying out the traps and when Scott Fraser played in Smith with 10 minutes gone it was with some ease that he fired the ball past Jags goalkeeper Ryan Scully, in for the injured Tomas Cerny.

After former United midfielder Chris Erskine cleared the crossbar with a drive at the other end, Smith made it 2-0 in the 27th minute when he raced onto a Tope Obadeyi flick, shrugged off the attentions of defender Callum Booth and slipped his shot past Scully and into the far corner.

He had to wait a further two minutes to get his third and it came after Scully had parried his powerful drive out to Blair Spittal.

The midfielder's goal-bound shot struck the hand of Firhill defender Ziggy Gordon and after referee Steven McLean pointed to the spot, the Scotland Under-21 international slammed the ball past Scully.

United, pacey and purposeful, threatened every time they came forward and three minutes from the break, Obadeyi's unorthodox shot from a Smith corner struck the bottom of the post.

Thistle substitute Ade Azeez, on for David Amoo, was foiled by United keeper Cammy Bell just before the break.

But, after Scully made a good save from Spittal's curling shot in the 54th minute, the visitors were given some encouragement when Lewis Toshney was adjudged to have fouled Erskine in the box and Welsh despatched the penalty.

Thistle left gaps as they went looking for a second and in the 75th minute Scully had to race from his goal to thwart Obadeyi before diving to parry an effort from substitute Simon Murray, on for Smith, and in the end the home side deserved to go into Wednesday night's draw.