Stuart Armstrong grabbed a double as Celtic warmed up for their crucial Champions League qualifier against Malmo with a 4-2 defeat of Inverness Caledonian Thistle on Saturday.

Mikel Lustig headed in the opener in the eighth minute before Leigh Griffiths nodded home a second four minutes later.

Armstrong sent a curling 55th minute strike past Owain Williams before making it 4-0 with a low drive in the 69th minute.

With the contest seemingly over substitute Ryan Christie pulled one back in the 71st minute with fellow substitute Dani Lopez halving the deficit seven minutes later.

The win keeps Celtic second in the Scottish Premiership on 10 points to continue their unbeaten start before Wednesday's visit of Swedish champions Malmo.

Hearts remain top of the table as they maintained their 100 per cent start to the campaign with a 2-1 win away to Ross County.

Scott Brown's return to captain Celtic after an absence of two games was one of five changes for the Hoops as Ronny Deila fielded a full-strength line-up following their midweek draw with Kilmarnock.

Celtic were on the front foot from the start and soon found themselves in front.

Stefan Johansen floated a free-kick to the far post where Lustig sent a header down into the turf and bouncing in.

Inverness barely had time to regroup before Celtic added a second.

Some fancy footwork on the wing gave Nir Bitton space to swing in a cross to the back post where Griffiths leapt above his marker to nod down in to the bottom corner.

A free-flowing passing move ended with a Johansen effort coming back off the bar before a follow-up shot from Stuart Armstrong was stopped on the line by Ross Draper.

Celtic goalkeeper Craig Gordon had been a virtual spectator but was called into action just before the break when he had to be alert to tip over a dipping shot from Andrea Mbuyi-Mutombo.

It took just 10 minutes of the second half for Celtic to add to their advantage.

Johansen's low shot was palmed away by Williams but Griffiths chased the ball down on the wing and picked out Armstrong, who sent a curling shot beyond the keeper.

Armstrong capped off an impressive display with a second strike in the 69th minute.

He strolled past three challenges on the edge of the box before cutting inside and drilling an angled drive into the bottom right-hand corner of the net.

Armstrong was then replaced by Callum McGregor while Inverness brought on Lopez and Nathaniel Wedderburn and the substitutes had an immediate impact as Inverness pulled one back two minutes later.

Substitute Christie took advantage of some careless possession to get in behind the Celtic defence and fire low past Gordon.

The visitors were celebrating again when Saidy Janko's slack pass out of defence found its way to Christie who set up Lopez for a strike from outside the box that had the better of Gordon.