Goals from Odsonne Edouard, James Forrest and Callum McGregor gave Celtic victory in the first leg of the Champions League first qualifying round tie against Alashkert.
In their first competitive outing of the season, Brendan Rodgers' side were tested in the searing Yerevan heat.
Celtic's superior finishing proved the difference as Edouard and Forrest struck either side of the break.
McGregor's goal at the death turned a good win into an emphatic one.
The second leg takes place at Celtic Park on Wednesday, 18 July.
Scotland's champions must negotiate an extra qualifying round if they are to make the Champions League group stage this season, with this the first of four potential ties.
The most intriguing aspect of the Celtic starting line-up was the decision of manager Rodgers, who so often deploys a lone striker, to pair French duo Moussa Dembele and Edouard in attack.
Dembele twice came close to finding the scoring touch in the opening minutes, almost intercepting a loose backpass and then just failing to apply the necessary contact to a superb Kieran Tierney cross.
A double scare soon came at the other end. Uros Nenadovic skipped away from Jozo Simunovic and his rasping drive had to be beaten away by Celtic goalkeeper Craig Gordon. Moments later, the Serbian striker tried his luck from the corner of the penalty area but his strike sailed over the bar.
Dembele drew a good save from Ognjen Cancarevic in the Alashkert goal as Celtic searched for the opener, while James Forrest found space and drove towards the box but could not keep his shot down.
Tierney was running Alashkert right-back Artak Yedigaryan ragged, with most of Celtic's joy emanating from that flank.
McGregor flashed a shot across goal and while the Scottish champions were well on top, they were given regular reminders of the home side's threats.
Artak Dashyan fed Nenadovic inside the Celtic penalty box and only a well-timed intervention from Simunovic prevented Gordon being called into action. Artur Yedigaryan then tried his luck from the edge of the box but the captain's shot was off-target.
Dembele was denied by Cancarevic after getting in behind the home defence but, just as it looked like the Armenian champions had made it to the break intact, Celtic struck in first-half stoppage time.
Edouard, who signed a permanent deal in the summer after a successful loan spell from Paris St-Germain last season, turned the ball home from 12 yards after meeting Forrest's mishit shot first time.
That should have settled any nerves in the Celtic ranks, but early in the second half defender Jack Hendry was robbed of possession by Jefferson Reis, who should have done much better than to tamely stab the ball straight at Gordon from 12 yards.
Cancarevic almost contrived to gift Celtic a second goal. The keeper raced from his goal to mop up a loose ball only to be dispossessed by Dembele, but managed to clean up his own mess before any damage was done.
With the temperature around 30C, and with early-season rust no doubt playing a part, Celtic were not exerting their superiority. Artak Yedigaryan stung the palms of Gordon with a fierce 22-yard strike as Alashkert threatened to level things up.
Cesar Romero and Reis saw chances come and go as the visitors began to sit in, seemingly content to take a one-goal aggregate lead back to Glasgow.
However, after a goalmouth scramble the ball dropped to Forrest to lash home Celtic's second 11 minutes from the end.
And with almost the last kick of the game, McGregor fired a measured low finish into the net to all but guarantee next week's second leg is nothing more than a formality.
Source: BBC NEWS