Jiraiya, who is gentler than Itachi. Despite this, Jiraiya was unquestionably weaker than Itachi. Even though Itachi stated that a confrontation with Jiraiya would result in both of them murdering one other, this was only to avoid conflict whenever possible, since his motives were always good. However, this does not mean that he could be defeated by anyone including himself.
The only way for Jiraiya to win would be if Itachi failed and died. But since Itachi swore to kill him if he ever used his Sharingan, this makes it impossible for them to fight.
However, this does not mean that Jiraiya cannot beat Itachi, as seen when he stopped Tsunade's attack with a single glance of his own eye. Also, Itachi did not murder him despite having the opportunity to do so; instead, he chose to spare his life because he wanted to continue their battle later on. This shows that Jiraiya was probably the strongest person alive at the time and could have easily beaten Itachi if he had wanted to.
Jiraiya, the famous Sannin's third and last member, was an extraordinarily skilled shinobi. During his lifetime, he trained others like as Nagato, Minato, and even Naruto, all of whom went on to become as powerful. They were once engaged in a battle to see who would win but during the fight, Itachi killed him with one stroke of his sword.
Mito Uzumaki was born into an old clan of ninja that was renowned for its use of genjutsu. He was also believed to be the reincarnation of someone very important in the history of Japan. However, due to many accidents caused by his enemies, Mito grew up feeling like a failure. He wanted to redeem himself so he decided to join the village modeld after hearing about its need from some friends. Once there, he found out that it was actually Hashirama who needed saving because he had been captured by Madara. Mito agreed to help Hashirama because he felt that he deserved to live again since he had saved someone important to Japan before he died. During the battle with Hashirama, Mito used his body as a medium to create a giant rock that blocked the path of Madara's army.
His power enabled him to confront Pain, the commander of the Akatsuki. Jiraiya and Itachi were thought to be equal in fighting capability, although Itachi was plainly far stronger than him, as seen by their accomplishments. His Mangekyo Sharingan was powerful enough to overpower Jiraiya. However, it is possible that with more training he could have been able to defeat Jiraiya.
However, what makes Itachi different from other Uchiha is his will to fight. He wanted to protect those who cannot protect themselves and fought against his brother when he became an enemy to humanity. This shows that even though he was greatly outnumbered, he did not back down from a fight. This proves that he can beat the Akatsuki because even though they are all Uchihas, they still have different powers which would make them easy to defeat one-by-one. Also, since he was able to overcome Jiraiya, who has the same rank as he does, we can assume that he would be able to defeat the other members of the Akatsuki too.
Now, this doesn't mean that Itachi will definitely win. Since the Akatsuki are supposed to be immortal, they will most likely not die until they are defeated. But since Itachi wants to protect people who cannot protect themselves, it means that he would do whatever it takes to win. So in conclusion, yes, Itachi can beat the Akatsuki.
Itachi was able to one-shot Orochimaru thanks to his genjutsu. Jiraiya, on the other hand, can battle with his eyes closed due to sage mode. Itachi's main power is genjutsu, and since Jiraiya can cope with it, I believe Jiraiya will defeat Itachi. Itachi isn't as powerful as Jiraiya. He could only fight against one opponent at a time.
In combat, they may be on equal footing. Due to achievements, this is doubtful, but Jiraiya has a lot of power and may be able to evade Itachi's genjutsu. Although, in my opinion, Jiraiya cannot defeat both Kisame and Itachi at the same time. Even though Itachi and Kisame felt they could fight Jiraiya, he didn't want to murder Jiraiya. He wanted to force him to teach him how to use his powers so he can destroy Konohagakure.
Also, note that Jiraiya can use any kind of genjutsu he wants against Itachi. Since Itachi is already aware that he is not real, there is no need for Jiraiya to use a genjutsu on him.