Predicts Goku would teleport to him to fire a Kamehameha

Then, as if something clicked in his mind, he suddenly felt foolish. 'I don't have time to toy with her. Had I not waited so long before now, she might have already been mine!'

Before he could pull his tail around, Goku appeared between them by Instant Transmission. The furious Saiyan had only one word.

"Kamehameha!"

He released the attack from point-blank range, putting all his energy into pushing Cell away from 18. Unlike his usual bright blue beam, this Kamehameha formed into a brilliant sphere that carried Cell away like a cannonball.

- Bringer of Death Chapter 51

As he expected, Cell dodged, but Goku was ready. Pulling back one arm and raising two fingers to his forehead, Goku used Instant Transmission to appear just behind his foe. The advantage allowed him to slam a haymaker into the back of Cell's head, dazing him. It gave Goku just enough of an opening to deliver one super-powered kick to the center of the monster's back.

...

"Goodbye, Cell!" he yelled.

TSSSHHHTT! The familiar hum of instant transmission sounded. Immediately, there was a blinding blue light, outshining the sun.

"HAAAAAA!"

The fury of the Kamehameha was deafening. The instantaneous explosion sent violent spherical shock-waves slicing through the ground in all directions. They cut deep into the earth, boiling water and shearing through solid rock. Vibrant blue light filled everyone's vision.

...

It was worse than they ever could have imagined. Even Goku, usually so cheerful, felt all his hope drain out of his body in an instant. How had he been so foolish, throwing all his energy into a single attack? It had been their last chance...but clearly something had gone wrong.

They all recognized the vibrant blue translucent sphere of energy surrounding Cell. It made perfect sense: Cell had absorbed Number 17, so he would have access to the android barrier shield. But who could have anticipated that Cell would have activated it at the precise moment, or that it could have withstood the overwhelming force of Goku's Instant Kamehameha?

...

"Well, Goku. It seems our little bout has finally reached a conclusion, however anticlimactic it was...for me at least. You relied too heavily on your Instant Transmission, and it cost you dearly. Did you think I wouldn't recognize it? It didn't cost me anything to throw up that barrier, and it left you utterly defeated."

- Bringer of Death Chapter 52