(CNN) -- Serie A leaders Inter Milan suffered a crushing 3-1 defeat at Catania on Friday evening, a result that throws the Italian title race wide open again.
On a dismal night for Inter coach Jose Mourinho, who had to watch the match from the stands because of a domestic ban, he saw midfielder Sulley Muntari sent off in the 81st-minute -- just two minutes after coming on as a substitute.
The result is the worse possible preparation for Inter, who travel to Mourinho's former club Chelsea in the Champions League last 16 next week, holding a slender 2-1 advantage from the first leg at the San Siro.
The result means city rivals AC Milan will cut their advantage at the top of the table to a single point if they defeat Chievo on Sunday.
There was no hint of the shock result to come, when Inter went ahead nine minutes after the interval.
Sanuel Eto'o collected a long ball from Dejan Stankovic and he found Diego Milito in space, leaving the Argentine striker with a simple tap-in.
The visitors seemed destined for the three points, until a dramatic last 15 minutes saw them concede three goals.
Catania levelled in the 75th minute when Maxi Lopez converted Jorge Martinez's cross from close range.
Then came Muntari moment of double madness, resulting in one of the quickest red cards in Italian football history.
The Ghanaian was shown a yellow card for a foul and he deliberately handled the resulting free-kick to concede a penalty and a second booking.
Giuseppe Mascara cheekily chipped home his penalty and the result was sealed in the final minute when Martinez out-foxed Lucio before cooly converting home Catania's third goal.