Defeats for Manchester City and Arsenal in the last 16 left Chelsea as the last of the title challengers still with European commitments - starting with Wednesday's trip to Paris St Germain.
Mourinho has regularly highlighted a lack of any European football this season as a key reason for Liverpool's improvement on last year, when they finished seventh.
And ahead of Saturday's trip to Crystal Palace the Chelsea manager, whose side go into the weekend with a one-point lead at the top, returned to a favourite theme.
He said: "We play Champions League, they don't. We have to play matches with two and three days in between, we have to change focus from the Premier League to the Champions League and back.
"Liverpool? They keep going in their perfect season. We have no time to prepare for matches like they have.
"I think it's a big advantage - an advantage that City have just now, and an advantage that Liverpool have had since the beginning of the season.
"When you have six days a week to prepare a match, six days to train maybe twice a day, you have conditions to improve that nobody else has.
"At the same time players have no accumulation of fatigue - you can see clearly that some of their players are not paying the consequences of (such) accumulation.
"You see freshness, you see that even players of a certain age don't need to rest for matches because they rest during the week. The season for them is a perfect season to do what they're doing."
Chelsea lead second-placed Liverpool by a point, with title favourites Manchester City two further back in third having played two fewer games.
And Mourinho says he will focus only on winning the next game and hoping that is enough come May.
He said: "We aren't in Man City's shoes but we are going to try to play well and win tomorrow. That's all we can do.
"We can win the league but it depends on the others. We have to try to win every game but even then you don't know."
As for Arsenal, now six points behind Chelsea following last weekend's Stamford Bridge hammering and a 2-2 draw with Swansea on Tuesday, Mourinho is not yet ready to write off Arsene Wenger's side altogether.
He said: "Mathematically it's open for them. It's more difficult because they're a few points behind the other three teams, but it's obviously possible."