The 2012 winners on Tuesday night play the Royal Blues, who have maximum points from two matches, at the Veltins Arena in Gelsenkirchen in their first return to Germany since lifting the European Cup in Munich.
Speaking at Dusseldorf Airport on the Blues' arrival in Germany, Mourinho said: "I don't think it's yet the time to have the calculator and to be counting the number of points you need to qualify, or to be first or second, or to go into the Europa League (as third-placed side).
"The calculator comes on the fifth fixture. The third and the fourth are still fixtures we can play just thinking about the game and trying to win, and if you cannot win try to get a point.
"We lost the first match at home (2-1 to Basel) but won the second away (4-0 at Steaua Bucharest), so we found a balance.
"We play two matches against the strongest opponent in the group, which leaves us the fifth and sixth fixture to play against Basel and Steaua.
"We need points over these two matches (against Schalke). That's obvious. But we're in condition to play without thinking about finishing first or second."
Chelsea and Schalke last met in November 2007 in the Champions League group stages, soon after the end of Mourinho's first spell as boss.
The Blues reached the final in Moscow in May 2008, losing on penalties to Manchester United, before winning the tournament four years later against Bayern Munich.
Last season Chelsea suffered the ignominy of becoming the first holders to exit the competition at the group stage and responded by winning the Europa League, a tournament Mourinho has no interest in.
To take control of Group E, Chelsea must beat a Schalke side who have won eight of their last 10 games, losing once to European champions Bayern.
But Schalke have a mixed recent record against English clubs in European competition.
They beat Arsenal at the Emirates Stadium 12 months ago, but lost heavily to Manchester United in the Champions League semi-finals in May 2011.
Mourinho's appraisal was simple.
"A good team, a good opponent," he said. "Hopefully we can be better than them."
Chelsea must do without Ashley Cole (ribs), who is absent, perhaps with Sunday's Barclays Premier League match with Manchester City in mind.
Schalke go into the match in buoyant mood with results both domestically and in Europe giving them no reason to fear the Londoners.
Although Royal Blues' coach Jens Keller has singled out Chelsea as "one of the favourites for the title", he believes there is no reason for his side to feel inferior.
"Just a glance at Group E as well as our recent results in the Bundesliga give us self-confidence, of course," Keller said.
"We're at home and Chelsea are going to feel that from the very first minute."
Keller is set to welcome Kevin-Prince Boateng back into his side after he missed the 3-2 win at Eintracht Braunschweig on Saturday with a knee injury.
"Things are looking good with him," said Keller, who should also be able to restore regular number one Timo Hildebrand in goal and Jermaine Jones in midfield for Marco Hoger, who has been ruled out for six months due to a serious knee injury.
Hoger joins Klaas Jan Huntelaar as a long-term member of the treatment room, but Keller prefers not to waste time worrying about the players he is unable to select, Jefferson Farfan and Kyriakos Papadopoulos included.
"We shan't talk about misfortune and feel sorry for ourselves," he said. "We've got to take the situation as it is.
"Every player who goes out there will give it their best."