London: "I'm a sore loser, I still am," says Garry Kasparov, Russian former chess grandmaster, recalling the game 20 years ago that marked the moment computers claimed the summit of chess from humanity.

"It was a big blow."

Almost exactly two decades on, at a talk in London this week, Kasparov tried to be – and sometimes succeeded in being – philosophical about his defeat.

He was honoured to be there at artificial intelligence's coming of age. "I was part of something big", he says, "but I still don't know whether it was a curse or a blessing".

He still bitterly rails against it, accusing the machine (or its owner IBM) of cheating.

And he is dismissive of Deep Blue's 'brute force' intelligence. It was a dead end that artificial intelligence (AI) is only just starting to emerge from, he says, with promising new approaches such as Google's DeepMind project.

That 1997 rematch against Deep Blue (Kasparov had won the first encounter the year before) was the first time he had ever lost a match.

"I cannot blame them for violating the rules," he says, of IBM who put Deep Blue up against him in 1997. "They played by the letter but not by the spirit."

Deep Blue, he says, "was strong but not superior" at the game itself.

But there was hanky-panky, he claimed. He was denied a look at his opponent's previous games (chess players usually study their opponents), the machine was rebooted a couple of times, and he got frustrated and flustered.

He thinks the IBM team behind Deep Blue may have been provoking him into losing his patience and composure.

"The way I played this match was way below the level of chess I was capable of in 1997," he says.

"I was really angry and I couldn't help comparing [a particular move in game 2] with Maradona's Hand of God."

Kasparov in his prime was an intensely human player – he saw the game as "psychological warfare", a "drama". 

But he acknowledges that if he hadn't been beaten in 1997, he would have been beaten sooner or later.

Now the free chess app you can get on your phone is stronger than Deep Blue. 

Deep Blue was "anything but intelligent", Kasparov says. It just ground through its options at lightning speed, considering its next moves much faster than humans are capable without truly understanding them.

But the sheer power in today's silicon technology applied to that same technique puts modern chess computers way beyond the game's human masters. Even the best humans make mistakes, and computers will ruthlessly exploit them.

However today's chess computers still lack something, Kasparov says – an element of creativity, a comprehension of strategy. They can waste a billion computer cycles looking at options that any decent player would immediately dismiss.

Even today a good player with a good chess computer will defeat the best chess computers. Humanity adds something – the ability to comprehend a game on an instinctive level.

He worries about the young chess players of today, who "look through computer lenses", training with chess computers and starting to think like them: "it is difficult to draw their eyes away from the screen so they can start thinking," he says.

Kasparov may call computers' dominance of chess a "hostile takeover" but has no time for technophobes and dystopian visions. For example in a couple of decades, he says, everyone will look back in horror that we ever drove our own cars, with the resulting road deaths and injuries.

"Anything that we do, and we know how we do it, machines will do it better," he says. "Instead of worrying about advances of artificial intelligence in the future, we should be concerned about the level of intelligence in the White House today."

But there will always be room for human creativity, says the now pro-democracy activist. 

"I am more concerned about the world in 50 weeks' time than in 50 years," he says. "I am an optimist."

He is excited by the DeepMind project, whose AlphaGo progeny has just defeated the world 'go' No. 1. He sees in its neural network, its trial-and-error learning of the game, something "a bit more human".

"Deep Blue was a dead end," Kasparov says. "It solved a problem but then there was nothing else it could do. AlphaGo is the beginning. It's something new."