Serena Williams continued her seemingly unstoppable progress towards a fourth Wimbledon title on Centre Court today but only after being forced to work overtime to dispatch inspired Czech Petra Kvitova.
Williams won 7-6 (7/5) 6-2 against the world number 62 who matched her for muscle from the start of a big-hitting contest and showed enough to suggest she will be back to challenge at the All England Club in years to come.
Williams had been expected to steamroller an opponent who was playing only her fourth senior level semi-final and to whom she had lost just three games in their only previous meeting in Melbourne this year.
But Kvitova's form has been there for all to see in a series of exceptional victories at the All England Club this fortnight, including a remarkable 6-2 6-0 success over third seed Caroline Wozniacki in the last 16.
From the start Kvitova's sheer aggression knocked Williams off guard as the Czech ruthlessly exposed the world number one's second serve and hit a series of blistering forehand winners.
Pumping her fist on almost every won point, Kvitova soon endeared herself to a Centre Court crowd desperate for a competitive match-up, even fashioning a break point, which she failed to convert, in Williams' first service game.
Kvitova went on to draw first blood in the fourth game when a flashing return on break point was too good for Williams, who found the net. Still playing almost flawless tennis, Kvitova held for a 4-2 lead.
Suitably stung, Williams responded by raising her game and starting to match Kvitova's power, forcing her opponent's previously solid forehand to go astray, and taking advantage of a string of unforced errors to break back for 4-4.
Williams then went on to clinch the first set on a tie-break, though it took her the last of three set points to do so, booming down an unreturnable serve to eventually clinch it 7-5 and move within one set of another final place.
Lesser opponents may have crumbled, but after saving a break point in her first game of the second set Kvitova once again proved undaunted by her situation, going on to hold to love for a 2-1 lead.
Even a Williams break in the fifth game did not quite snuff out the Kvitova challenge, as the left-handed Czech flung winning forehands to extend the world number one to three deuces in the following game.
She was forced to finally accept defeat when Williams double-broke on a double-fault for 5-2 - though not before Kvitova had saved the first break point against her with a forehand winner at the end of an extraordinary 19-stroke rally.
It was the kind of challenge which was overdue for Williams after she had breezed into the semi-finals without losing a set, although strangely the American insisted she had started the tournament in sluggish fashion.
Williams said: "I didn't expect to get this far at the beginning of the tournament. I just felt off but I'm happy to still be here. I think maybe it's because I'm just Wimbledon-crazy."
On her final opponent Vera Zvonareva, Williams added: "Vera's a great player. I've had some unbelievably tough matches against her so she's really tough. I feel like I've got nothing to lose going into the final, and neither does she."