Basel inflicted Chelsea's first home loss in the group phase of the tournament in nearly 10 years, ending a 29-match unbeaten streak, at the start of Group E, leaving the Blues and returning boss Mourinho fearful of a repeat of the 2012-13 season.
The Blues suffered the ignominy of becoming the first winners to exit the tournament at the group stage in defence of their title, before responding by beating Basel in the semi-finals en route to winning the Europa League.
Since the Basel blow on September 18, Chelsea have responded with a 4-0 win at Steaua Bucharest and two 3-0 defeats of Schalke, the early pace-setters, and they require one point to advance to the next round, while a fourth win would seal top spot in the pool.
Mourinho hopes to secure Group E at St Jakob Park, so that the result in the home match with Steaua on December 11 is an irrelevance.
"We are going to try to win and kill," Mourinho said.
"We have so many matches in December that if we can have one less - and the one less is the crucial match against Steaua - it would be a help.
"We are going to try to win. In the end if you get a point you qualify, you have a point, but we have to try to win the game there.
"Also because it was not a good feeling to lose against them at home - so, no revenge, nothing, not at all, but to try to win against a team that beat us at Stamford Bridge I think is important."
Chelsea's December schedule sees them play nine times, with Southampton at home in the Premier League followed by fixtures against Sunderland - a side the Blues also face in the Capital One Cup next month - Stoke and Crystal Palace.
There is a trip to Premier League leaders Arsenal on December 23 and home matches with Swansea and Liverpool to complete the calendar year.
Mourinho insists he is not yet thinking about the Arsenal contest at the Emirates Stadium.
"Let's see how we arrive there," he said.
"Who knows what happens? Who knows in which position we are and they are on December 23? Who knows?
"Maybe they are third and we are fifth? You never know. In this Premier League, anything can happen.
"Just play match after match and see what happens. "(Winning at West Ham) was important to win because if we lose we are seven points from them (Arsenal) and seven points in this league is not dramatic, but seven points are seven points."