Just hours after Paolini beat tearful Croatian Donna Vekic 2-6, 6-4, 7-6 (10/8) in the longest women's semi-final at the All England Club, it was Krejcikova's turn to dig deep for victory against fourth seeded Rybakina in two hours and seven minutes on Centre Court.
Krejcikova faces seventh seed Paolini on Saturday in what will be the second Grand Slam final of the 28-year-old's career after her French Open triumph in 2021.
"I'm so proud about my game and my fighting spirit today," said Krejcikova.
The Czech started 2024 with a run to the quarter-finals of the Australian Open, but a first round exit at the French Open was a major setback.
She struggled with a back injury and illness, winning just three singles matches in the five months before finally finding her form in remarkable style at Wimbledon.
Krejcikova shocked 11th seed Danielle Collins in the fourth round and former French Open champion Jelena Ostapenko in the quarter-finals, before turning her sights on Rybakina.
The two-time Wimbledon doubles champion is now one win away from an unexpected triumph in the singles.
"Unbelievable. It is very tough to explain, but a lot of joy and a lot of emotions," Krejcikova said.
"When I broke her in the second set, I started to be in the zone and I didn't want to leave the zone."
Rybakina had been in formidable form, dropping just one set as she extended her impressive All England Club record to 19 wins from 21 matches.
The 25-year-old, who won Wimbledon in 2022, made a fast start with two quick breaks for an early 4-0 lead in a one-sided first set against Krejcikova.
In her first Wimbledon semi-final, Krejcikova turned the tide in the second set, landing a priceless break in the sixth game.
She levelled the match on her sixth set point, making it the first time in 20 years that both Wimbledon women's semi-finals had gone to the final set.
The Czech held all the momentum and she eventually wore down Rybakina, who had committed over 35 unforced errors by the time she surrendered her serve in the decisive, seventh game of the final set.
"Barbora played very well but I think it's still a positive tournament for me," said Rybakina.
'I will remember this forever'
Paolini had never won a main draw match at Wimbledon before this year, but the world number seven tenaciously saw off Vekic in two hours and 51 minutes to secure a second successive Grand Slam final appearance.
The 28-year-old, who lost the French Open final to Iga Swiatek last month, is the first Italian woman to reach the Wimbledon final.
Paolini, who also made the Australia Open last 16 in January, had not gone past the second round in any Slam before this year.
Without a win at the All England Club heading into the tournament, Paolini now has six victories under her belt and has dropped just two sets in the process.
"The last months have been crazy for me. It is a dream. I was watching finals when I was a kid on this Wimbledon," she said.
"You know there is no place better than here to fight for every ball and every point. I will remember this forever."
Vekic paid the price for 57 unforced errors, with the semi-final fittingly ending on another wild forehand from the unseeded Croatian.
Unable to contain her frustration at letting 3-1 and 4-3 leads slip in the last set, Vekic broke down in tears in the closing stages of a rollercoaster clash.
"I was crying because I had so much pain. I didn't know how I could keep playing," Vekic said.
"I thought I was going to die in the third set. I had so much pain in my arm, in my leg."
