The received wisdom is that experiencing new things in life is the key to vitality as one gets older.It can safely be assumed, though, that dropping points to St Johnstone for the first time in his managerial career would not have been Martin O’Neill’s idea of a fun night out.Some 24 years after last locking horns with the Perth men, the 74-year-old chalked up a seventh win in as many games against them to enhance the feel-good factor around Parkhead.Aside from a desperate night away to LASK in the Champions League qualifiers, the Scottish champions haven’t missed a beat this season.With a Europa League opener against Ferencvaros the meat in a sandwich of two forthcoming clashes with Rangers, O’Neill’s men are entitled to feel pretty good about themselves right now.This outcome stretched Celtic’s winning start to six games in the league and, in doing so, surpassed the total reached under Brendan Rodgers last season. Mika Baur celebrates his second-half winner over St Johnstone at McDiarmid Park Baur wheels away in delight after his effort hits a net in Celtic’s narrow victory in PerthFor all the disquiet that followed that bleak night in Austria, the club feels more united than it did 12 months back as the Honda Civic began to leak oil.While a much-changed Celtic side were by no means scintillating in Perth, they got there in the end with a performance that was more battling than brilliant.Mika Baur’s tap-in early in the second half arrived just when you wondered if the lack of zip O’Neill’s side were showing in the final third might cost them.Having failed to find the second goal to kill the game off, the veteran would have felt a few nerves before breathing a sigh of relief at full-time.St Johnstone competed throughout. They fashioned some half chances and a one in the first half which Joel Cotterill really ought to have buried. Simo Valakari’s men will play worse and win matches.With Yang Hyun-jun away on international duty and a raft of new signings itching to be involved, intrigue surrounded O’Neill’s selection and how his team shaped up.While the Celtic manager stood by his favoured 4-3-3, some of the names present and missing from the starting side were eye-catching.Viljami Sinisalo dropped out with Sam Johnstone making his debut in goal. Cameron Carter-Vickers didn’t even make the bench, apparently rested due to fatigue.Camilo Duran, six goals in six games, was held in reserve as were Benjamin Nygren and the returning Kieran Tierney. Dane Murray, Oliver Sorensen, Seb Tounekti and Kasper Hogh were also introduced.Seeking to build on a solid start to the season, Valakari brought in Daniel Finlayson, Matty Todd, Cotterill and Hibs loanee Josh Campbell. Josh Fowler began the night up front as the Premiership’s top scorer. Celtic boss Martin O’Neill looks on in the dugout as his side made it six top-flight wins out of sixHanding three stands over to Celtic supporters is entirely St Johnstone’s prerogative, but there’s no question that guaranteed cash in the bank does diminish home advantage.O’Neill’s men certainly started like they meant business, Hogh stubbornly arguing that an early Saints’ free-kick was being taken two yards further up the field than it ought to have been.Tounekti, you feel, could learn a thing or two by looking at the man who’s currently lighting up Celtic’s right flank.Haissem Hassan is as direct as they come for a winger. He didn’t hesitate to try and take on his opposite number whenever the opportunity arose here. Tounekti’s instincts often saw him check back and recycle the play.Both wingers featured in Celtic’s first real chance. Tounekti dropped a shoulder, cut inside and found Hogh who in turn rolled in Hassan. Toby Steward in the home goal ushered the Egyptian’s low strike around the post.Tounekti then gathered a smart pass. He just couldn’t find the killer ball which would have given Sorensen the chance to open his Celtic account.With the visitors dominating the early stages, Hassan’s deep cross looked inviting for Baur. The German just didn’t have the speed to wrap his left foot around it.Saints found their feet and began to ask some questions of their own. Enes Alic got the better of Colby Donovan and crossed. Cotterill took it first time. Johnstone threw up his fist and beat the shot away. Valakari roared his approval.With their opponents well organised and gilt-edged chances proving hard to come by, Celtic began to get frustrated. Another Hassan cross was met by the head of Sorensen. This one was blocked by the back of a Saints defender.Tounekti again did the hard part by turning Daniel Finlayson inside out. To his manager’s dismay, his cut-back was nowhere near a team-mate. Far too often in the first half, they failed to capitalise from promising positions.Slackness began to creep into their general play. Donovan twice gave the ball away under no pressure and was fortunate that Johnstone wasn’t called into action. Auston Trusty was next to err with a loose pass with Donovan getting back in place to block Taylor Steven’s strike.There was no sign of St Johnstone trying to ease their way into the second half. Straight from the restart, Reece McAlear showed great strength to ride a couple of challenges. Steven’s shot had power but lacked the accuracy to really trouble Johnstone. Saints’ Matty Todd tries to evade Celtic winger Sebastien Tounekti in a hard-fought matchWith too much of their play going from side to side, O’Neill urged his players to take more responsibility. The words had barely passed his lips when they did just that and the opener duly arrived.Fair play to Tounekti. Not a great deal had come off for him when he created half a yard and crossed. Hogh had to twist his body to keep possession but succeeded in finding Hassan. The winger did Cheick Diabate for speed, found the line and crossed low.For once, the ball evaded Saints’ entire defence. Baur applied a composed finish at the far post to claim his first Celtic goal.St Johnstone were compelled to open up and go for an equaliser. Inevitably, the price to pay was leaving more space for Celtic to exploit.Hassan almost put the game beyond them, his clever curling effort tipped away by Steward.Brought on with 17 minutes remaining, James Forrest followed up some close control on the edge of the box with a curling strike which worked the Saints keeper.Saints kept believing. Alic’s ambitious left foot strike from an angle flashed narrowly past Johnstone’s far post. Steward then produced a fine pair of saves to deny Hogh and Nygren in short order.You felt Saints were bound to get one last chance. It fell to substitute Ruari Paton in injury time, but his strike was too central to beat Johnstone.Although it was by no means a sparkling display by Celtic, they merited the victory which keeps them rolling along nicely.