“In this competition the tactics are not the most important thing,” Guardiola told a news conference.
Manchester City coach Pep Guardiola stood by his decision to shake up his side's tactics in their Champions League quarter-final against Olympique Lyonnais after his team suffered a shock 3-1 defeat by the unfancied French outfit.
Guardiola strayed from the 4-3-3 formation with which his side had outclassed 13-times winners Real Madrid in the last 16, instead fielding a back-three including vastly inexperienced Erik Garcia, 19, as the central defender.
"In this competition the tactics are not the most important thing," Guardiola told a news conference.
"They (Lyon) are so fast and our central defenders are not so quick so I didn't want to leave them two versus two.
"We worked for three days on this, we discussed it and we reviewed this and when you play like we did in the last 20 minutes it shows the system is not the problem."
Garcia was badly caught out of position for Lyon's second goal, while the defence also slipped up badly for the opening strike from Maxwel Cornet, who was allowed a free strike at goal from outside the area.
"I don't know why it didn't work but I know why we played this way," added the Catalan.
"We struggled in the first 25 minutes but in the second half we felt free, we were there and I had the feeling we were better than them but you have to be perfect in this competition and we were not."
City fell behind to Cornet's strike in a sloppy first half and although they looked like their usual selves after the break and levelled through Kevin de Bruyne, they were downed by two strikes from Moussa Dembele, sandwiched between an unbelievable open-goal miss from Raheem Sterling.
"It is what it is and hopefully one day we'll break this gap in this competition," added Guardiola, who has led City to two Premier League titles in four seasons but never gone beyond the quarter-final stage in the Champions League.
"We created more chances, had more shots, we did everything but unfortunately we are out again."
Guardiola did not complain about Lyon's second goal, which survived a VAR review after a potential foul by Dembele on City defender Aymeric Laporte.
"I don't know, I don't want to talk about those circumstances because sometimes it seems like I'm complaining or looking for excuses. We are out, I had the feeling we were incredible already, but we made mistakes in the boxes in the key moments."
He also rued Sterling's astonishing miss which would have made it 2-2 and was promptly punished by Dembele's second goal which was the killer blow.
"That moment sums up this competition, we had to equalise and after we conceded the third goal," he said.
"That's this competition, you have to be perfect."