(CNN) -- Ronaldinho plundered a hat-trick as AC Milan crushed 10-man Siena 4-0 on Sunday to close the gap on Serie A leaders Inter Milan to just six points and with the Milan derby to come next week. 

Milan also have a game in hand meaning they could potentially draw level with the four-in-a-row champions if they were to win next weekend's crunch clash. 

The hosts started in determined mood following Inter's 2-2 draw at Bari on Saturday and Ronaldinho took an Alessandro Nesta cross on his chest on three minutes before sending a spectacular overhead bicycle kick just off target. 

But on 10 minutes the referee took the decision that essentially ended the game as a contest. 

Jardim Brandao dithered on the ball in his own box and Marco Borriello dispossessed him before trying to go round goalkeeper Gianluca Curci. 

There was minimal contact and Borriello crumpled to the ground but the striker's last touch had been too heavy and left him no chance of reaching the ball before a back-tracking defender. 

Even so, the referee pointed to the spot and showed Curci a straight red card. 

Substitute goalkeeper Gianluca Pegolo's first task was to pick the ball out of his net. 

Siena battled on gamely, and on 26 minutes Massimo Maccarone escaped three defenders on the edge of the Milan box to bundle through before firing over on the stretch as Thiago Silva came across to put him under pressure. 

Two minutes later the lead was doubled as Andrea Pirlo curled a cross into the near post and Borriello hooked a brilliant volley over his shoulder and into the top corner. 
was the contact maximum?
There was minimal contact 