HEARD the one about the Englishman, American, Swede, Croatian, Aussie, Portuguese, Greek, Japanese and three Scotsmen?

No, this isn't the start of a bad joke. Far from it.

In fact, it was the national identity of every member of Ange Postecoglou's Celtic's starting 11 that defeated St Johnstone 2-0  at Celtic Park as they reduced the gap at the top on Rangers to just one point - for 24 hours at least.

The United Nations of Celtic stars certainly showed a united front as they made heavy weather of seeing off Callum Davidson's double domestic cup winners from last season.

When all was said and done the Hoops had racked up a third Scottish Premiership win on the spin (four in all competitions) and a third successive clean sheet.

You get the feeling that Postecoglou hasn't even started this managerial malarkey yet as he attempts to mould this Celtic side in the image of himself as well as give the supporters the all-out attacking and exciting football that he promised from day one.

The feel-good factor from Tuesday afternoon's confidence-boosting 2-0 Europa League Group G win over Ferencvaros continued unabated.

An impressive 19-minute cameo from Greek striker Giorgos Giakoumakis against the Hungarians had the Celtic fans purring and Socratically stroking their chins in anticipation.

To a man, woman and child the Celtic fans all left the East End amphitheatre in midweek hoping to see more of last season's Eredivisie's top scorer.

Postecoglou knows a thing or two about philosophy - football-wise that is.

The question on every Celtic's supporters lips before today's encounter was thus would Postecoglou be prepared to tweak that philosophy to accommodate Giakoumakis?

The fans were not to be disappointed.

When the teamlines dropped the manager had duly obliged as the former VVV Venlo hitman got the nod to start his first 90 minutes.

The Aussie stuck to his system and tactics with a 4-3-3 formation. Giakoumakis was through the middle with Japanese striker Kyogo Furuhashi and Jota occupying both flanks.

Israeli wide man Liel Abada was the unfortunate one on this occasion as he was cast to the sidelines.

Elsewhere in defence, young Adam Montgomery was replaced by Croatia international left-back Josip Juranovic who returned after a month out injured.

This was the strongest Celtic side that had been available to Postecoglou since he took over at the managerial helm.

READ MORE: Detailed Celtic player ratings as Giorgos Giakoumakis nets on full debut against St Johnstone

For the first time, this season the Aussie had options - lots of them.

It was the visitors who started the brighter of the two sides and the Perth men offered stubborn resistance in the first 30 minutes with a Callum McGregor drive being saved by the boot of Saints goalkeeper Zander Clark the pick of the moments for the hosts.

Saints would have done well to beware Greeks scoring goals. The all-important breakthrough finally arrived in 34 minutes and it was Giakoumakis who stepped up to the plate.

Ralston was the provider as he crossed into the box and Giakoumakis showed lightning reflexes to adjust his position and volley home a beauty from eight yards.

It was a great and instinctive finish from the Greek attacker who was up and running for the campaign.

To be fair this was as comfortable as it gets for Celtic who enjoyed 82 per cent possession in the first half.

The crowd was eagerly anticipating a second goal that would put the contest to bed once and for all.

The passing was crisp and there was an element of control and composure but Celtic hadn't fashioned many clear-cut chances as the clock ticked down.

Giakoumakis made way for Mikey Johnston just after the hour as Celtic pursued a clinching second goal.

As the game wore on, Chris Kane should have walked after appearing to kick and strike  Cameron Carter-Vickers on 77 minutes. Referee Nick Walsh disagreed and incredulously booked both players as Paradise threatened to erupt.

It was all over - bar the shouting - on 80 minutes when Juranovic cemented all three points as he coolly slotted home from the penalty spot to make it 2-0 after Kyogo had been upended in the box.

It wasn't a vintage Celtic performance by any stretch of the imagination but it was the third successive 2-0 victory and that is what matters.

Postecoglou's men are beginning to build up a head of steam and the fact it was the two men he brought into the team - Giakoumakis and Juranovic - who made the difference by scoring the goals will please the boss even more.

This Celtic side is a multi-cultural entity and, whilst the players may not all speak the same language off the park, they are most certainly communicating fluently on it.

Postecoglou knows only too well that the only football word that matters for Celtic right now is 'vincente, vinnande, epitychís, katsu, ganhando, osvajanjem'.

It means the same in any international language. It's called winning.