The early qualifying session saw Andretti and Unser set the pace. Both drivers wanted to fly back to Indianapolis, Indiana for the Hoosier Hundred at the Indiana State Fairgrounds, a 100-lap race on the 1609 metre (one mile) dirt track for the USAC Championship the next day. They then intended to fly back to Milan and race in the Grand Prix. The event organisers announced that if the either driver returned to the US, they would be banned from competing in the Grand Prix, under an ACI ruling which forbade drivers to complete in another event within 24 hours of the start of the Grand Prix. Both drivers flew back to Indiana for the Hoosier Hundred and did return for the Italian Grand Prix, but were not allowed to take part in the race.[1]
The race was held over 68 laps of the Autodromo Nazionale di Monza, taking place in sunny conditions, with Surtees leading from the start. McLaren and Surtees fought for the lead, until the Ferrari of Chris Amon lost control on oil dropped by one of the Honda RA301s and his car flew over the barriers into the trees at one of the fast Lesmo corners. Surtees also hit the wall trying to avoid the Ferrari. This put Jo Siffert into second place, with Jackie Stewart third. The Scotsman moved into second and a slipstreaming battle developed for the lead between McLaren, Stewart, Siffert and Denny Hulme.[1][3]
McLaren's M7A had to stop for more oil on lap 35 and retired. Stewart retired on lap 43 when his Cosworth engine failed. Hulme was by this stage already leading the race, and when Siffert went out with a rear suspension failure, nine laps from the end, Hulme was left to win. He won in a time of 1hr 40:14.8mins., averaging a speed of 146.284mph. There had been a battle behind him, between Johnny Servoz-Gavin, Jacky Ickx and Jochen Rindt. The Ferrari of Ickx had emerged ahead, only to stop in the closing lap for more fuel. In the process, he dropped to third behind Servoz-Gavin, while Rindt had to retire with an engine failure. Piers Courage, Jean-Pierre Beltoise, and Jo Bonnier rounded out the top six, with no other finishers.[1][4]
