Manchester City manager Pep Guardiola said he was saddened by the departure of Gabriel Jesus, Oleksandr Zinchenko and Raheem Sterling but that the income generated from their transfers had helped the club’s sustainability.

The Premier League champions sold Jesus and Zinchenko to Arsenal for reported fees of £45m ($55m) and £30m, respectively, in the end-of-season window.

City, who have consistently ranked among the biggest spending clubs in European football in recent years, have also let Sterling join Chelsea in a deal worth up to £50million.

They have breached UEFA’s Financial Fair Play rules in the past, which sought to limit overspending, although they limited their penalty by winning an appeal to the Court of Arbitration for Sport.

“Partly I’m a bit sad that these important players are gone,” Guardiola told reporters ahead of the City Shield game against Liverpool later on Saturday.

“But it’s a business. To invest you have to sell players, otherwise you can’t be sustainable. I know the image of the club is that we are always buying, buying, buying. But we also sell. We sell big players for big money.

“All clubs now know that selling players is not easy. All clubs want to do it but not everyone can.”

City begin their Premier League title defense with a trip to West Ham United on August 7.