Nope not saying he was invincible although Black Zetsu did say so...
Anyway in part 1 itachi was the most powerful. True hefelt the ms drawbacks butits not likekakashi made him tired like you are trying to say. Kakashi got beat pretty easily. The ms wore itachi out not kakashi, itachi used that jutsu to prove a point that uchiha sharingan>random clan given sharingan. He could have easily beatkakashi in a basic skills battle of clones taijutsu and kunai as seen how amazed kakashi was at just how fast itachi handsigns were. He never had any intent on killing kakashi nor any konoha member.
Same for jiraya he has no counter for tsukoyami he would have spent a week in the hospital next to kakashi. Itachi showed Amaterasu at that time that amazed jiraya as to how he escaped the toad mouth. No way jiraya could win, like I said it's a manga fact itachi didn't want to harm any pro konoha shinobi. He merely said that as to not have to give up his true self to kisame whoknew and said itachi could beat jiraya. Kisame is probably the best shinobi in ideals of what one should be, gai, and yamato praised kisame for his dedication as a shinobi after kisame killed himself. So why would he lie. Kabuto exposed itachi as a bigger liar and manipulator than him during the Uchiha Bros vs Kabuto fight.
Part 1 itachi is a liar and was protection konoha at all times, so why harm konohas biggest weapon Jiraya?
If you can't say how jiraya in part 1 canavoid tsukoyami then that's further proof of itachi not wanting to harm pro konoha shinobi so he said it would be a tie. Part 1 jiraya only had rasengan and toads and wack as jutsu. He would have gotten stomped by taukoyami and amatersu.. He didn't have sm in part 1 either.
