The Belarusian, who has a tiger tattoo on her left arm, powered to victory on Court One and will face either Ons Jabeur or defending champion Elena Rybakina in the last four.
Second seed Sabalenka broke in the first game of the match, converting a fourth break point with a sweet backhand that sailed just over the net and out of the reach of Keys.
She broke the American again, giving her no time to think and launching every ferocious shot with a matching howl.
Sabalenka served out the set after 38 minutes, looking the favourite to reach her second semi-final at the All England Club having done so on her last appearance in 2021.
However, Keys, chasing her first Wimbledon semi-final, came out in the second set with more grit and determination. After holding serve at 3-2 with a backhand winner, the American pumped her fist and shouted "come on" as she looked to level things up.
The 25th seed had three break points in the next game and took the third when Sabalenka sent a forehand wide.
But the Belarusian broke straight back, winning five points in a row from 40-0 down to snatch the momentum from Keys and she fired down an ace to level at 4-4 before breaking again and serving out the match.
"I can't wait to play my second semi-final at Wimbledon and hopefully I can do better than last time. It was a really tough match, really great player and super happy I was able to win the second set, (and the) game," Sabalenka said on court.
"Thank you so much for the atmosphere, even though you support her more!" she added with a smile, which drew applause from the crowd.
