Marco Andretti branded IndyCar Series rival Mario Moraes 'clueless' after the pair clashed on the opening lap of the Indianapolis 500, ending any hopes either had of winning the blue riband event for the first time.

Opinion remains divided over who was most to blame for the incident, with Moraes equally happy to blame the youngest member of the Andretti dynasty - and seek physical confrontation following his release from the infield medical centre - but most versions of events suggest that he moved up the track at turn three, only to find Andretti coming on the high line. Andretti then hit Moraes' KV Racing Technology entry, knocking him out of the race.

"What do you want me to say? What does he want to hear?" the Brazilian fumed, "I think that Andretti did a really unnecessary move when he was on the outside. I was in the front and I was holding my line. That was the first lap but, at the first corner, he was already outside. I don't know if he knew, but this is a 500-mile race. I don't know if there was any point in what he did."

Moraes also admitted that there had been no warning as to his rival's presence.

"I hadn't heard anything from my spotter to know he was there, he didn't tell me that [Andretti] was looking outside," he said, "I was just driving my line and, when I realised, I was in the wall. It was not a nice way to finish this month when we had such a good car and a really good chance of at least finishing in a top five."

Andretti, meanwhile, was a good deal more out-spoken, ignoring his own youthful status to attack Moraes after the pair started alongside each other on row three.

"The kid doesn't get it," he blasted on air, "He never will. He was clueless out there. I was worried about that at the start. The warning was who I'm racing against. That kid is in way over his head with where he is now. I'm sitting next to him and he just drives up into me. There was no one in sight of him. I should have known better."

Andretti's exit continued the family's run of back luck - branded by some as a curse - that stretches back three generations. Mario Andretti suffered no fewer than 20 misfortunes that outweigh his sole triumph, and his trip to Victory Lane in 1969 remains the last for an Andretti, despite the best efforts of son Michael and, now, grandson Marco. Michael Andretti, now co-owner of Marco's Andretti Green Racing team, holds the record for most laps led at the Brickyard without having taken victory.