- Luca Caldirola (78')
A late goal by defender Luca Caldirola earned promoted side Monza a shock 1-0 win at Inter Milan in Serie A on Saturday as Simone Inzaghi's men slumped to a fourth loss in their last five league outings.
Inter, who are on course for a first Champions League last-four appearance since 2010 following their 2-0 win at Benfica in their quarterfinal first leg on Tuesday, needed three points to return to the top four.
For Inter, who recently fell to three consecutive league losses against Spezia, Juventus and Fiorentina, and drew 1-1 last weekend at Salernitana, it was their third home loss in a row for the first time in 10 years.
"It was a photocopy of [our games against] Fiorentina and Salernitana, we are very disappointed and angry," Inzaghi told Sky Sport.
"It's not true that we don't feel the championship but only the cups. We knew the importance of this match, it is a negative result that slows down our path."
Inter forward Joaquin Correa could have made it 1-0 in the 24th minute when he concluded a pair of one-twos with a low shot from inside the box, only to be brilliantly denied by the alert Monza keeper Michele Di Gregorio.
After a first half short of clear chances and quality, Inter gradually pushed for a goal and Di Gregorio pulled off another superb save to deny Romelu Lukaku's header shortly before the hour mark.
The Belgium striker had one more chance a minute later but his curled shot from the edge of the box went wide.
In the 64th, Monza were close to finding a goal through almost an identical strike by forward Dany Mota.
The visitors took a surprise lead at the San Siro in the 78th minute through Caldirola, who met a corner and nodded home from close range, with the ball bouncing off the ground into the top left corner.
Substitute Lautaro Martinez was Inter's best bet to look for an equaliser but one of his closest attempts was denied by the goalkeeper and another went inches wide of the left post.
Heroic Monza, who held Inter to a 2-2 draw in the reverse fixture in January, moved up one place to 12th on 38 points.
"I'm proud of these guys. We've made history, winning at San Siro is wonderful," Monza coach Raffaele Palladino said after they moved 15 points clear of the relegation zone.
"We want to score as many points as possible. I haven't [named] a position [to the guys], we have to do our best. If they finish in a higher place, every single guy gains value. Each of us must raise the bar."
Monza next host Fiorentina on April 23 when Inter travel to 14th-placed Empoli.
- Luca Pairetto