This game may have been irrelevant in terms of final Champions League group standings, but it was not a wasted evening for Patrick Roberts. On loan from Manchester City to Celtic, Roberts scored against and frustrated his parent club to end Celtic's European campaign on a positive note.

City were already assured of second spot in Group C and Celtic bottom before kick-off here, but the numerous personnel changes by Pep Guardiola made for an open, even and entertaining match.

Celtic played with attacking verve and provided City with a constant threat. This was not the kind of dour and defensive display often seen in previous years by Scotland’s champions, but one that will give Brendan Rodgers much optimism going forward.

Patrick Roberts celebrates his opener for Celtic (Getty)

There were some scuffles between opposition supporters in the closing stages, but on the whole this was a match played in good spirits by two sides intent on scoring. Kelechi Iheanacho demonstrated his sharpness with the equalising goal, but Roberts was the one that shone and Guardiola cannot have failed to notice his future potential.

Roberts, signed by City from Fulham for £11m in July 2015 and having made one Premier League appearance as a substitute for the club, made his mark on the game after just four minutes, during a frantic start in which City’s three-man defence struggled to settle. Gael Clichy and Bacary Sagna played either side of teenager Tosin Adarabioyo, but the new-look defence looked vulnerable early on.

Kelechi Iheanacho leveled the score after Patrick Roberts' early opener (Reuters)

Guardiola made nine changes from the weekend defeat to Chelsea and it took a few minutes until his players relaxed into the game. That was not before Roberts had demonstrated his qualities against his parent club, darting inside and beating Clichy for agility and pace before finishing coolly past Willy Caballero whose poor ball out gave Celtic the scoring opportunity in the first place.

Roberts was a constant threat and Guardiola could have been forgiven for pondering why this talented attacker was lining up in the black of Celtic instead of the Manchester blue. Leroy Sane, playing left wing-back for City, was regularly required to check back and keep taps on Roberts instead of making runs forward himself. He could have also had a penalty shortly before half-time, with Clichy appearing to hold him back on the edge of the area.

However, while Roberts shone throughout, Celtic's lead only lasted four minutes. Ilkay Gundogan – alongside Sane the only player who remained in the team from the Chelsea loss – started the move in central midfield, finding Nolito who split the Celtic defence with a precise through ball to Iheanacho. The youngster accelerated onto the pass and finished emphatically, into the top corner with the outside of his right foot.

Pep Guardiola issues orders from the sideline (Getty)

Iheanacho is poised for an extended run in the City first-team following Sergio Aguero’s four-match suspension, and Guardiola will take heart from a performance that showed the striker is in sharp form.

In the 11th minute he flashed a left-footed effort wide after Pablo Zabaleta had put him through, and shortly before half-time he was denied a superb backflick goal by Craig Gordon’s excellent close-range save.

Nolito takes a shot on during the first half at the Etihad Stadium (Getty)

Celtic could have gone in front again had Moussa Dembele not sliced his shot into the side netting when rounding Caballero, but Rodgers’ side were playing with an attacking confidence that has become commonplace this season.

Tom Rogic flashed a shot over the crossbar in the 63rd minute as both sides sought an equaliser, the game open and quickly moving from one end to the other. Nolito had a goal ruled out for offside – just straying past the last man before finishing Navas’ low cross – and the substitute Leigh Griffiths scuffed a shot two yards wide in the 78th minute.

In the end there was to be no winner, but it was Celtic’s fans singing loudest at the final whistle.

Manchester City (3-5-2): Caballero; Sagna, Adarabioyo, Clichy; Maffeo (Navas 62), Sane, Gundogan, Fernando, Zabaleta; Nolito, Iheanacho. Subs not used: Gunn, Aguero, Stones, Otamendi, Tasende, Foden.

Celtic (4-2-3-1): Gordon; Lustig, Simunovic, Sviatchenko, Izaguirre; Brown, Armstrong; Roberts, Rogic, Forrest (Mackay-Steven 51); Dembele (Griffiths 73). Subs not used: De Vries, Toure, Bitton, Gamboa, McGregor.