And at Twickenham today, Alexander will reignite his Lions rivalry against the likes of Mako Vunipola, Tom Youngs and Dan Cole.
But the tight-head, who started in all three Tests for the Wallabies, believes it will take a long time before Australia restore their reputation on the world stage.
"The way that third game went was heart-breaking," he said. "For us, we'll never get that chance again.
"We're just left with what-ifs. It definitely was the most disappointing moment in my career.
"I don't think it will erase (the memory) if we perform well.
"It won't really clear it up until a World Cup semi or final when the scrum performs that people will finally go 'the scrum is solid'.
"Our problem has been consistency. You are not going to win a World Cup unless your scrum is consistent. I don't think we'll ever silence the critics until that happens."