Pep Guardiola channelled his inner Jurgen Klopp for Manchester City's first pre-season clash of the summer.

After the Kenan Memorial Stadium was evacuated 90 minutes before kick-off for a severe weather warning - despite glorious blue skies overhead - Guardiola was first out onto the pitch in Chapel Hill when the all clear was given. He stayed out for the warm-ups, later taking a seat pitchside, in what is a departure from his usual routine before a game.

The manager usually prefers to let his coaches lead the warm-ups, sometimes sitting in the dugouts for a short while before retreating when his players emerge. Here, he watched everything, even the Celtic preparations, and was animated throughout a testing evening for his young squad.

Guardiola said in the build-up that he feels refreshed and excited for the new season. A new tactic was on show, too. Or a new twist on an old tactic.

Rico Lewis, who declared his ambition to play in midfield this week, was back at full-back, inverting inside to accompany Kalvin Phillips. On the opposite side, Josh Wilson-Esbrand did the same, creating a double pivot of full-backs alongside Phillips, who would drop deep alongside the two young centre-backs on show.

It was a system that looked promising, but Celtic quickly exposed it. Phillips almost put Stefan Ortega into danger in the first minute, and the Scots led when Luke Mbete pressed a ball that was never his, Phillips followed him, and Nicholas Kuhn had the freedom of North Carolina to finish.

Wilson-Esbrand didn't know whether to stick or twist, and did neither. But Celtic are four games into their tour, this is City's opener and with a squad predominantly made up of academy players. If they learn from their mistakes it can be a useful experience.

Nico O'Reilly, in his first senior outing, was promising and hit the side-netting, while captain Erling Haaland was coming out second best in a duel with former City keeper Kasper Schmeichel. O'Reilly collected Jack Grealish's pass, Haaland dummied, and Oscar Bobb's shot squirmed under Schmeichel to level the scores.

Only for a minute, though. Once again Phillips was caught out far too highly up the pitch, Wilson-Esbrand couldn't work out where to be, and Kuhn had a second. Guardiola was furious on the touchline, waving and gesturing and pointing at his midfield. Or where his midfield should be.

If Phillips was being given a chance to launch a stunning comeback of his City career, he could in fact have been making his situation worse. Once again he was yards off the play, pushing far too high, as Kyogo Furuhashi collected a smart ball over the heads of the two centre-backs and finished smartly.

Phillips, unsurprisingly, was hooked at the break as one of four outfield changes. And within 30 seconds, one of his midfield replacements pulled one back - Maximo Perrone slotting into the bottom corner following Bobb's mazy run. Phillips didn't see it - he took ten minutes to emerge from the dressing room and appeared to receive treatment when he did appear.

Bobb backed up his pre-match declaration that he was in the right place to progress with another assist, this time standing up a cross for Haaland to power home - a popular goal for the 31,000 fans in attendance. These are the opportunities he must take, and that is exactly what he did.

Celtic won the game on the break but by that time Ederson was the only senior player on show, as well as the 19-year-old Lewis. Guardiola still stood attentive pitchside watching his players carry out his instructions. He said he was back refreshed and ready to go - and his agitation in North Carolina proved it.

2024/25 is up and running, with Guardiola dropping some interesting clues over how he wants to play. But some players might have already played themselves out of contention.