Atletico and Tottenham have been paired today in the round of 16.
Alemany reacted, stating: "We know that either team would be extremely difficult. Their European campaign has been brilliant. A top Premier League team, extremely challenging. We have to focus on our own performance and respect our opponent.
"We have to take it absolutely seriously, we are in the top competition, against a rival of the highest demand, the highest difficulty.
"The important thing is that we have an important match tomorrow and another crucial one on Tuesday in Barcelona. There are still matches to play before Tottenham."
Atletico meet Oviedo in the LaLiga before the Copa del Rey semifinal second-leg at Barcelona.
Alemany added, "It's a very important match (Barca), that's clear, but the round of 16 and the league are also important. We have to be in all three competitions.
"Now it's Oviedo's turn. We're going there with the hope of staying alive in all three competitions, especially the Cup and the Champions League, where we have a better chance."