In a major upset the 23-year-old Briton and world No49 beat the Bulgarian No3 seed in four sets in Melbourne.
Kyle Edmund has become only the sixth male British tennis player to reach the semi-finals at a Grand Slam tournament in the Open era, after beating third seed Grigor Dimitrov at the Australian Open.
The world number 49 came through in four sets, 6-4 3-6 6-3 6-4 to see off the Bulgarian. The 23-year-old, who had never previously been beyond the fourth round in a major tournament, showed little sign of nerves with an impressive display.
The Yorkshireman will play either number 1 seed Rafael Nadal or sixth seed Marin Cilic in the last four on Thursday.
Speaking by the court on the Rod Laver Arena immediately after his victory, Edmund said it was an "amazing feeling".
"You're so emotionally engaged that you don't really take it in, you don't enjoy yourself, so just at the end, after a hard match and having played lots of matches so far, I just really tried to enjoy the moment," he added.
Edmund’s compatriot and Davis Cup teammate Andy Murray, absent through injury, took to Twitter to express his delight. Apart from Murray, no other British man has reached the semi-finals at Melbourne since December 1977 – and the last to get to this stage of any Grand Slam apart from the Scot was Tim Henman in 2004.