Benfica interim coach Nelson Verissimo said on Tuesday that Ajax are "one of the best teams in Europe", but the Dutch side's manager Erik ten Hag responded that "favourite does not matter" ahead of the two sides' Champions League last-16 first leg.
The Portuguese giants welcome the Dutch champions to the Estadio da Luz on Wednesday, looking to reach the quarter-finals for the first time since 2016.
But Ajax won all six of their group games and only Bayern Munich scored more goals in this season's competition heading into the knockout stages.
"We are going to face an opponent with a lot of quality," said Verissimo, who took over at Benfica until the end of the season when Jorge Jesus was sacked in December.
"Ajax are currently one of the best teams in Europe. They have strengths, but also weaknesses that we'll want to exploit.
"We know it will be difficult, but we are motivated. We have to keep possession, and also defend without the ball. Honestly, I think it's 50/50."
At his press conference, Ajax coach ten Hag, responded that Benfica were also dangerous.
"We want a good result, knowing who is favourite does not matter. We have analysed Benfica. They take advantage of mistakes," he said. "Counter-attack is one of their strong points."
He also praised the Benfica defence built around two 34-year-olds: Nicolas Otamendi and Ajax old boy Jan Vertonghen.
"The strength of Benfica is their experience, especially in the centre of defence," said ten Haag. "We will have to be very good to create opportunities because they have experienced players like Otamendi and Vertonghen."
Benfica qualified from their group at the expense of Barcelona but have struggled since Jesus' dismissal, losing the Portuguese League Cup final to Sporting Lisbon and slipping 12 points behind league leaders Porto.
But Vertonghen believes playing in the Champions League again will be a breath of fresh air for his team.