Manchester City failing to replace Vincent Kompany in the summer was their biggest mistake ahead of the season.
The Citizens saw their influential captain leave the club after his contract expired last summer. Guardiola and company made attempts to sign a replacement but ultimately decided to trust in their options.
It came crashing down for City when Aymeric Laporte was ruled out long-term for five months due to an inury.
It left Guardiola short of options so bad that Guardiola had to deploy Fernandinho in defence on a number of occassions.
A faltering defence was the undoing for City and by the time Laporte returned, Liverpool already looked likely to be crowned champions.
Pundit Graeme Souness evaluates their season so far and believes that was the one thing that saw the Citizens fail to defend their title.
“That’s cost them dearly this year,” Souness said as quoted by Express.
“I think Fernandinho’s played 20-odd games at centre-back.
“You go back to the start of the season, Kompany goes.
“Pep would have said the very last player I want to get injured this year for any amount of time would be Laporte.
“Even if Kompany had stayed, getting 15 to 20 games out of him, they were still a centre-half short.
“So with Kompany going and Laporte having his long-term injury, that cost them dearly, big time.”