Manchester City are already working on how they can improve next season after sealing a spot in the Champions League, manager Pep Guardiola said as he mulled over potential targets in the summer transfer window.

City secured a top-four finish for the sixth consecutive season with a 5-0 win over Watford on Sunday but Guardiola failed to win a trophy for the first time since 2009, after enjoying widespread success at Barcelona and Bayern Munich.

"We are satisfied because we are in the Champions League, and tomorrow we will think about what we need to do next season, when the pressure will be the same," Guardiola told reporters after City sealed third place with the victory.

"Next season we will be better, and as a coach I am better than the year before, but it is not simple."

Guardiola said that the top Spanish sides were better placed to lure who they wanted in the transfer window as they had the money and stature to attract top talent from other clubs.

"Real Madrid have just bought one player, 16-years-old (Vinicius Junior) for 46 million euros ($51.37 million), so you can imagine the market," Guardiola said.

"To compete with Barca and Real we need time, we need decades to be there. Money is not enough -- when Real and Barca want a player, other teams cannot compete."

The Spaniard noted City's progress in the past few years but said that there was still work to do before they were comparable with Europe's elite.

"Before, we were never in the Champions League, and now we have been there six or seven times in a row. But, to achieve the next step, although the gap is shorter, it is more difficult." Guardiola added.

"To close the gap you need time, and in our world time doesn't exist, it's not allowed."