Celsus would not even grant him foreknowledge
Celsus could, however, have accepted or conceded that Jesus foreknew what would happen to him, and then made it seem a trivial thing, as he did with the miracles when he said they were done by sorcery. He could indeed have said that many people, through divination by omens, by birds, by sacrifices or by horoscopes, have known what was going to befall them. But this he would not concede, as being the greater thing; whereas he has in a way accepted that Jesus worked the miracles, and seems to have discredited this under the pretext of sorcery.
Phlegon, however, in the thirteenth or fourteenth book, I think, of his Chronicles, even granted Christ foreknowledge of certain future events, although he confused what concerned Peter, taking it as said of Jesus; and he testified that the things foretold turned out as Jesus had said. Yet even he, through what he says about foreknowledge, declared, as if against his will, that the teaching found in the fathers of our doctrines was not without a more divine power.
Greek
Ἐδύνατο μέντοι παραδεξάμενος ἢ συγχωρήσας ὁ Κέλσος τὸ προεγνωκέναι αὐτὸν τὰ συμβησόμενα αὐτῷ ἐξευτελίζειν μὲν τοῦτο δοκεῖν, ὅπερ πεποίηκεν ἐπὶ τῶν δυνάμεων, γοητείᾳ φάσκων αὐτὰς γεγονέναι, καὶ ἐδύνατό γε λέγειν ὅτι πολλοὶ ἀπὸ μαντειῶν, τῶν ἐν οἰωνοῖς ἢ ὄρνισιν ἢ θυτικῇ ἢ γενεθλιαλογίᾳ, ἔγνωσαν τὰ ἀπαντησόμενα αὐτοῖς. ἀλλὰ τοῦτο μὲν οὐκ ἠθέλησε συγχωρῆσαι ὡς μεῖζον, τὸ δὲ τὰς δυνάμεις πεποιηκέναι παραδεξάμενός πως δοκεῖ αὐτὸ προφάσει γοητείας διαβεβληκέναι. Φλέγων μέντοι ἐν τρισκαιδεκάτῳ ἢ τεσσαρεσκαιδεκάτῳ οἶμαι τῶν Χρονικῶν καὶ τὴν περί τινων μελλόντων πρόγνωσιν ἔδωκε τῷ Χριστῷ, συγχυθεὶς ἐν τοῖς περὶ Πέτρου ὡς περὶ τοῦ Ἰησοῦ, καὶ ἐμαρτύρησεν ὅτι κατὰ τὰ εἰρημένα ὑπ᾿ αὐτοῦ τὰ λεγόμενα ἀπήντησε. πλὴν κἀκεῖνος καὶ διὰ τῶν κατὰ τὴν πρόγνωσιν ἄκων ὡσπερεὶ οὐ κενὸν θειοτέρας δυνάμεως ἀπεφήνατο εἶναι τὸν ἐν τοῖς πατράσι τῶν δογμάτων λόγον.