AC Milan star Zlatan Ibrahimovic tested positive for coronavirus on Thursday but responded: "Covid had the courage to challenge me. Bad idea."

"I tested negative to Covid yesterday and positive today," said Ibrahimovic, who turns 39 in a week's time, on Twitter. "No symptoms whatsoever. Covid had the courage to challenge me. Bad idea."

The Swede is now self-isolating and missed the team's Europa League third qualifying round tie against Norwegian club Bodo-Glimt in the San Siro Thursday.

The positive test is a blow for Ibrahimovic who has been in stunning form despite his advancing years.

He scored a double in Milan's Serie A opener against Bologna on Monday having also netted against Irish side Shamrock Rovers in the Europa League.

"It is a heavy, unexpected absence," said Milan technical director Paolo Maldini. "He was very sorry because he is in overflowing physical condition and unfortunately has an ongoing infection.

"The hope is to eradicate the disease soon and be available again. In seven days he will be available in my opinion," added Maldini.

Ibrahimovic is expected to miss the next two Serie A games against Crotone and Spezia. 

The Swede will most likely be available again after the international break for the Milan derby against city rivals Inter on October 17.