Sequence 9 - And Ther're Off
The last discipline can be found near the ship.  This is hard race. First, you run across the street. 
Then start jumping using some various elements on the right wall.  After a few seconds turn left and jump on the white building. 
Go around the corner.  After a while we climb on the roof and use ropes. 
Return to rooftops and run again.  At the end jump into the water, get out of it and run.  The race will end when you will reach the ship.
Sequence 9 - Cheaters Never Prosper
Finally, we can begin final discipline.  Your task appears to be very simple - win with another players using your feasts. 
After a moment Dante will fight with you but he won't be a problem too..  Unfortunately, Silvio will send some soldiers against us. At this point, you have to disarm them and finish with their weapons.  You will not get the mask now. Get back to Antonio.
Sequence 9 - Having a Blast
We need to get the gold mask. Run through the streets of the marked area and look for Dante.  He will be walking somewhere. Hide in a nearby group of courtesans and wait until he will pass near you. 
Now get close to women that are walking behind him.  Get close and rob him (standard procedure), then run away  and go to the party.
When Ezio will be at the proper place he will change masks. You can pass through guards now.  You will meet your sister, who will suggest to hide among girls. 
Few moments later, Dante will appear and will command to search for Ezio. Hire a girl and try to avoid guards with their help.  After one minute your target will appear. 
Marco is in a boat surrounded with many soldiers. You have your precious gun so use it. Hire a courtesan and go with her to a wall near the boat.  Now, target Barbarigo and shoot him. 
Now you must disappear. Just jump into the water and swim to the other side.  Now, go back to your sister and Antonio.