Chelsea can claim the Premier League crown with wins against Leicester tonight and Crystal Palace on Sunday.
But Mourinho is already bracing himself for a tougher title race next season next season's title race will be a whole lot tougher.
And he reckons Arsenal - who went through the 2003-4 season unbeaten - Manchester United and Manchester City will be spending big in the summer to stop Chelsea getting off to another flying start.
"Arsenal have a phenomenal squad," said Mourinho. "On Sunday night Thierry Henry said they need four top-class players.
"Give Arsenal four top-class players and I think they will be the Invincibles again.
"Man United have a phenomenal squad, including the most expensive player in the history of the Premier League (£60m Angel Di Maria), who is not playing.
"So you see the quality of the squad. They are a club where Financial Fair Play doesn't make a big difference and they will invest hugely again in the summer.
"City have done phenomenally, winning two titles in three years, and people say they will invest hugely.
"Liverpool fighting for the title for many years. So next year it will be even more difficult for everyone than this year.
"How can you speak about domination when everyone knows what will happen in the summer?
"At this moment, it's very difficult in the Premier League for a team to be dominant.
"This is not Germany with Bayern. This is not Switzerland with Basel. This is not Scotland with Celtic. It's very difficult."
Even so, Chelsea have set a blistering pace and Mourinho is full of pride for the way his squad adapted to life after club legend Frank Lampard.
Mourinho added: "Chelsea lost what I consider for sure, for sure, for sure one of the five most important players in the history of Chelsea FC - Frank Lampard.
"We lost that player. But life goes on. You have to think about the future and to build.
"Because, with Frank Lampard, Chelsea lost a matchwinner.
"With the number of goals he scored, a big character, a player without injuries who played every game, a player who beat every record in the Premier League - playing time, number of goals, midfield goals - an absolutely amazing player. We lost him, but life goes on."
