Sporting Lisbon coach Marco Silva warned his team cannot afford to keep making mistakes following Tuesday's win over Maribor.
Silva's Sporting edged closer to the UEFA Champions League round of 16 thanks to a 3-1 win against Maribor in a Group G fixture that was delayed due to a power cut at the Estadio Jose Alvalade.
The Portuguese hosts were on track for a routine victory thanks to goals from Carlos Mane and Nani before the 32-minute mark but a Jefferson own goal gave Maribor hope approaching half-time.
Islam Slimani eventually restored Sporting's two-goal lead in the 65th minute.
Sporting are in the box seat to advance to the last 16 with one matchday remaining after leapfrogging Schalke by two points, though Silva was not totally convinced by his team's display.
"Our focus is on the Champions League and we want to go through to the last 16," Silva told UEFA.com.
"Today only a victory mattered and we got that victory, justifiably.
"We did not start the second half well because we had had the game under control and conceded a childish goal near the interval, which allowed our opponents to regain confidence.
"We cannot keep making mistakes like that."
Silva, however, was pleased with loanee Nani, who jinked past three defenders and fired the ball beyond Maribor goalkeeper Jasmin Handanovic for Sporting's second goal of the game.
"We are collectively strong which makes individuals like Nani shine more often. Today he scored another great goal and we are happy for him," Silva added.
Nani - on loan from Premier League side Manchester United - has scored six goals since returning to Portugal, with four of those coming in the Champions League.
"Things are going well for me at the moment. I'm very involved in the matches and that's what I want - to contribute to the success of the team," said Nani.
The Portugal international winger added: "My goal was a lot of effort, dribbling past players and when I finally managed to score it was almost a relief.
"I celebrated like that because I have to think about the people I care about more, like my son, and I wanted to dedicate that goal to him."
Tuesday's defeat left Maribor at the foot of Group G, though the Slovenians have not given up hope of qualifying for the Europa League ahead of Schalke.
"We started the second half well, with a high tempo, but then we lost a bit of concentration which allowed Sporting to score the third and clinch it," said coach Ante Simundza.
"We are out of the Champions League now but we can still reach the Europa League and we will fight for it in our last match."