Lyon coach Remi Garde struck a cautious tone after seeing his side take a 1-0 lead over APOEL after the home leg of their Champions League last 16 tie here on Tuesday.
Lyon dominated the game at a wintry Stade Gerland but had only a solitary goal from Alexandre Lacazette to show for their efforts at full-time and Garde warned that the tie was far from over.
"We're at half-time in the contest," he said. "We're 1-0 up, so nothing has been achieved yet -- far from it.
"I can't estimate our chances. It'll be difficult and we'll have to be ready for a challenging situation."
Both Garde and APOEL were experiencing the knockout phase of the Champions League for the very first time and the 45-year-old coach praised his side for the way they negated the Cypriots' counter-attacking threat.
"The objective was to score goals and not concede any against a team that defends deep and breaks quickly," he said.
"Our defensive rigorousness allowed us to win the ball back high up the pitch. Our patience with the ball made sure we didn't lose our heads in attack and allowed us to find the opening."
Bafetimbi Gomis was left on the Lyon bench despite having scored five goals in the group phase and APOEL succeeded in keeping the hosts at bay in the first half, with Lacazette squandering their only clear sight of goal.
The in-form 20-year-old proved a steady source of danger though and he made the breakthrough in the 58th minute, cutting sharply onto his right foot and ripping a shot past APOEL goalkeeper Dionisios Chiotis.
"I started with him tonight because he has a vivacity, both with and without the ball, that is very useful in attacking areas," said Garde of the France Under-21 international.
It took the visitors until the 88th minute to muster a shot at goal but OL goalkeeper Hugo Lloris preserved his side's precious clean sheet by touching away substitute Gustavo Manduca's left-footed shot.
Although Lyon are competing in the last 16 for the ninth consecutive season, they have only progressed to the quarter-finals once in the last five years -- when they reached the semi-finals under Claude Puel in 2010.
While Garde refused to speculate about how APOEL would approach the second leg, he conceded that Lyon were likely to face a greater examination of the defensive frailties that have dogged them in recent weeks.
"I can't know the plans of the opposition coach," said Garde, whose side had conceded the opening goal in their previous four outings.
"They have to score, so they'll have to attack, but we'll be ready for any scenario."
APOEL will dread the prospect of an away goal for Lyon in Nicosia on March 7 but their Serbian coach Ivan Jovanovic vowed that his club's fans would see a different side to their team in the return leg.
"In terms of effort, the players gave all they had, but I think that we can play much better," he said.
"I said yesterday (Monday) in the press conference that Lyon had great quality, so the result is normal and a fair reflection of what the teams showed on the pitch.
"The level is totally different (in the Champions League). Of course it will be difficult, but we'll still try our best to get through. Anything can happen in football."