CELTIC warmed up for the rigours of their Champions League qualifier against Azerbaijan’s Carabag in midweek with a solid work-out against a top-class French outfit at Parkhead.
Ronny Deila will no doubt be delighted with the performance of virtually two Hoops teams – only Efe Ambrose remained on the pitch for the full 90 minutes.
In the end, it was comfortable although, to be fair, Rennes came more into the game after the interval and substitute keeper Leo Fasan had to make two excellent saves.
All in all, Celtic look in good shape for the first leg test against the dangerous Carabag in the east end of Glasgow on Wednesday.
Leigh Griffiths, after rattling in a hat-trick last Saturday in the 4-1 win over Eibar in Spain, got the show on the road with a wonderful solo goal in the 13th minute.
The in-form frontman teased and tricked his way in from the right before abruptly and unexpectedly swivelling and drilling a low left-foot drive between the keeper and his near post.
It was the sort of impromptu touch that will be more than welcome against Carabag when a little piece of individuality may be required to prise open a stubborn, blanket defence.
Rennes were a technical, compact outfit, content to soak up pressure and quick to hit on the break. They possessed a lot of skill, but were struggling to cope with Celtic’s pace and vigour.
In the 21st minute, Craig Gordon had to be alert when Morrera fizzed in low 25-yarder. The keeper got down swiftly to his right to hold the ball confidently.
Two minutes later, the Celtic fans were celebrating a second goal and it was all down to some smart thinking by the SPFL champions when they were awarded a free-kick.
The ball was shuttled to Stuart Armstrong, taking over Stefan Johansen’s midfield role, who wasted no time in pushing the ball into a pocket of space in the penalty area.
Gary Mackay-Steven, his former Dundee United team-mate, read the situation and his timing was perfection itself as he came in on the blindside from the left before slipping the ball with ease past the exposed keeper.
Gordon made certain the Hoops held onto their two-goal advantage just before the half-hour mark after the French outfit carved out an opening on the right.
The defence appeared slow to react to the danger and a Rennes attacker was given a clear sight of goal. He banged the ball low and hard, but the shotstopper sprawled to his right to push the effort away and Dedryck Boyata completed the clearance.
There was a scare for the champions, though, in the 36th minute with Mulgrew limping and Emilio Izaguirre coming on.
The Scotland international, of course, has been jinxed by injury this year and Deila took him off immediately rather than take a risk with an important Euro tie coming up.
Certainly, the Hoops gaffer looked relaxed enough as Mulgrew took his place in the dug-out.
Throughout the first-half, Griffiths and Mackay-Steven looked lively up front and their movement was exceptional, but James Forrest toiled to impose himself on the game.
As expected, Deila made a raft of changes at the start of the second-half with only Izaguirre and Ambrose remaining on the pitch from the 11 on show up until the half-time intervention.
Ambrose moved into central defence with former Manchester United Swiss Under-21 international Saidy Janko taking over at right-back.
Nadir Ciftci, playing in midfield, set up a great chance for unmarked Stefan Scepovic, but the Serb screwed the ball wide of the target. His blushes were saved by the linesman flagging for offside.
Sub shotstopper Fasan made a brave and athletic save when he came off his line to throw himself full-length at a long ball into the box to punch clear with considerable power.
Just before the hour mark, Janko powered down the right and sent over a delicate cross with Scepovic lurking at the far post. A French defender frantically headed clear for a corner.
Understandably, with so many half-time changes, the fluency didn’t match that of the opening 45 minutes, but Celtic still played neat and controlled football with Janko taking the opportunity to shine in front of his new fans.
He got a rousing cheer when he danced past two challenges as he cleared up a situation in his own half before bombing down the right flank. The youngster, who was taken to Old Trafford by ex-boss Davie Moyes, looks a genuine prospect.
Joe Thomson, taking over from captain Brown, also impressed in his midfield role. He was busy and eager during his second-half showing.
Italian kid gloves Fasan again rose to the occasion when he made a spectacular high-flying save to his left in the 74th minute to push away a ferocious header that was arrowing in at his top left-hand corner of the net.
At the other end, Ciftci managed to manoeuvre into space about 25 yards out, but the Turk tugged his finishing effort wide of the upright.
Stokes, celebrating his twenty-seventh birthday, almost got on the scoresheet with a cute inswinging right-foot shot, but it carried just over the bar and dropped onto the top of the net.
And Fasan was alert again minutes from time when he pushed the ball away with his left hand with a French attacker racing clear of the defence.
TEAM: Gordon (sub: Fasan 46); Ambrose, Boyata (sub: O’Connell 46), Van Dijk (sub: Janko 46), Mulgrew (sub: Izaguirre 36); Brown (sub: Thomson 46), Bitton (sub: Rogic 46); Forrest (sub: McGregor 46), Armstrong (sub: Giftci 46) , Mackay-Steven (sub: Stokes 46); Griffiths (sub: Scepovic 46).