Blake, who would later reach two US Open quarter-finals, was in Augusta for a sweat test, having struggled with cramp during the tournament.
His father, though, was still in New York, where he worked. With mobile phone networks overloaded, there was an uncomfortable wait to discover he was safe and well.
Blake was living in Florida at the time, and with planes grounded, took a hire car from Augusta back to Tampa.
His next tournament was in Hong Kong two weeks later, and he admits it was far from easy to board the plane.
“It was definitely scary because I think you get so isolated in tennis,” he said.
“You feel like the little bubble you are in, where you are a kind of travelling circus, is normal.
“And then when you realise how restricted travel can be, it wakes you up a little bit to the reality and how quickly things can change.
“It felt like there was a safety net around you. We lived in a bit of a dream world where you are living your dream of playing a sport for a living, and that can all be taken away.”
Many domestic sporting events were paused in the aftermath of the attacks, and the Ryder Cup – which had been scheduled to take place at The Belfry in England later that month – was postponed by 12 months.
In Blake’s view, the return of competitive sport helped enormously.
“I think that was one of the things that brought the country back,” he said.
“Sports were stopped, but when they came back having [then President] George W Bush throwing out the first pitch at a Yankees game – I’m not a Yankees fan, and I can’t say I was necessarily a George W Bush fan – I was almost in tears at that moment.
“It was special to have a sitting president [do that]. And it also signified we are back – we are going to have sports, we are going to continue on with our lives.
“The world seemed like it was back on track in a small way.”