Atletico Madrid coach Diego Simeone says his team's looming Europa League semifinal with Arsenal is a "50-50 tie" and Arsene Wenger's side were the "strongest side" left in the draw.
Atletico visit Arsenal's Emirates Stadium for the first leg on Thursday, April 26, with the return on Thursday, May 3 at the Wanda Metropolitano, and the winner facing either Marseille or Red Bull Salzburg in the final in Lyon on Wednesday, May 16.
The rojiblanco boss told a news conference ahead of Sunday's La Liga game at home to Levante that Arsenal's history in European competition and "very important manager" would provide a stiff test for his side.
"They are possibly, for history, the strongest opponent," Simeone said. "With an important history in Europe, a very important manager and with good players. It is a 50-50 tie for both sides."
Atletico reached the last four by beating Sporting Lisbon 2-1 on aggregate, with Simeone's men indebted to goalkeeper Jan Oblak for vital saves in both legs against the Portuguese side.
Arsenal are among the many clubs reportedly tracking the €100 million rated Slovenia international, with Oblak himself having suggested recently that he was surprised not to have been offered a pay-rise from Atletico.
"Atleti are working trying to keep their most important players, who sustain the team," Simeone said. "Jan is the best in the world at the moment. I hope he stays with us, and we can show him that we are improving as a team and as a club.
"I hope he remains happy and improving where he is today. All teams who end up winning things do so as they have great goalkeepers."
Centre-forward Diego Costa and defender Lucas Hernandez were substituted with thigh and facial injuries [respectively] on Thursday night in Lisbon, leaving to Simeone having to name two youth teamers in his match squad for the first of five games in 15 days.