Nicky Clark's controversial penalty sent Dundee United on their way to the Ladbrokes Premiership play-off final with a 3-0 victory over Inverness.

Clark slotted home in first-half stoppage-time after Brad McKay was harshly penalised for handball by referee Kevin Clancy.

Visiting boss John Robertson was sent to the stand at half-time after making his feelings clear and Osman Sow netted his first goal for United 10 minutes into the second half before Pavol Safranko scored late on to seal a 4-0 aggregate win.

United will now host either Hamilton or St Mirren on Thursday night in the first leg of the final as they look to make it third time lucky in the play-offs.

Inverness had Tom Walsh back fit to replace the suspended Liam Polworth, whose red card had a major bearing on United's 1-0 first leg win.

The visitors started on the front foot but Peter Pawlett was looking dangerous for Robbie Neilson's side.

Several Joe Chalmers corners caused problems for United but Benjamin Siegrist showed brilliant reactions to stop Walsh's deflected volley before Jordan White sent a free header over from six yards.

Inverness had an even better chance just after the half hour mark when Aaron Doran ran on to McKay's ball over the top but the skipper hesitated slightly and Siegrist blocked his shot.

United were looking nervous and sloppy in possession but they came back into it and got the breakthrough in contentious circumstances.

Clark laid Ian Harkes' low cross back to Pawlett, whose shot was well blocked by the foot of McKay. But the ball spun up off the defender's arm and Clancy pointed to the spot.

Clark faced a delay as McKay protested but the former Rangers striker made no mistake.

United soon removed all doubt about the outcome. Harkes' diagonal ball allowed Paul McMullan to run at Kevin McHattie and the winger eventually forced the ball to Sow, who turned inside the six-yard box and finished high into the net. It was the former Hearts striker's first goal in 10 matches for the club.

An offside-looking Clark hit the outside of the post following a cross from Safranko before the forward repeated the trick from a glaring opportunity.

McKay knocked the ball out of goalkeeper Mark Ridgers' hands to leave Clark with an open goal but the striker hit the post from three yards.

The home fans in the 8,540 crowd were in full voice and Safranko sparked more celebrations with 10 minutes left when he slotted home following fellow substitute Sam Stanton's pass.