The 26-year-old has impressed at the heart of the Gunners midfield during their first unbeaten three matches of the new campaign, having seen his progress during the 2011-12 season blighted by injury problems.
France international Diaby is now eager to gain as much playing time as possible.
Diaby told Le Parisien: "I had some very difficult moments, some days when I was depressed when it was tough, but even then, I always kept faith.
"I always told myself that some people were in a worse position than me.
"I am 26 and I am aware that I am at a key moment in my career, that is why it was so important that I came back this season.
"Now, I am careful about every detail, I leave nothing to chance. I am much more mature. I also had a full pre-season for the first time in ages."
Diaby added: "It is such an important season for me that I am working harder than ever to succeed.
"I want to prove to myself that I can go higher.
"I am getting to an age and to a time in my career where I need to show what I can do on the pitch in the long term."
Diaby's return to full fitness saw him called up to France's squad for World Cup qualifiers against Finland and Belarus, alongside Arsenal team-mates Olivier Giroud and Laurent Koscielny.
The powerful midfielder admitted there was a point where the constant injury setbacks started to play on his mind.
He said: "Last season, before the Fulham game, I was shaking on the bench because I was scared of getting injured again. It was incredible.
"All I wanted was to play again. I am born with a strong temper. I never give up. Maybe some people would have given up in my position, but it was out of the question for me.
"It was my destiny, it was written (to come back). I had to fight to put an end to all those injuries and to be able to express myself on a pitch again."
Gunners boss Arsene Wenger has been away this week attending the UEFA elite club coaches forum in Nyon, Switzerland.
Arsenal saw plenty of movement during the summer transfer window, with Nicklas Bendtner one of the players allowed to leave on loan to Juventus rather than sit on the bench.
Despite the Denmark striker insisting he had no future at Arsenal, having spent last season at Sunderland, Wenger can see the day when the 24-year-old features for the Gunners again.
"It is not for nothing that I loaned him to Juventus. He is a talented player. There he will grow and then return to my team,' Wenger told Italian sports newspaper Tuttosport.
"I am convinced that at a team like Juventus, in a very difficult league, especially for strikers, he can make the final leap in quality.
"Don't forget, he is a boy of 24 years. The right age to prove who he is.
"The talent is not missing; otherwise I would not have bought him from Copenhagen when he was just 16 years old."
Wenger continued: "We believe in him and that is why we only gave him to Juventus on loan.
"We have not sold him, only loaned him, and next year we will bring him home.
"I think he can resolve his problems with us and prove himself."
Arsenal striker Marouane Chamakh was unable to link up with Morocco for their African Nations Cup qualifier in Mozambique because of a virus.
The 28-year-old had been recalled to his national team for the first time since being dropped during the 2012 Nations Cup finals in Gabon.
Chamakh did not travel because of illness, but Press Association Sport understands reports the player had contracted malaria are inaccurate.
Despite the sale of captain Robin van Persie, Chamakh - who joined Arsenal from Bordeaux in May 2010 - has yet to feature for the first team this season.
Meanwhile, midfielder Chuks Aneke, 19, has joined npower League One side Crewe on a one-month loan deal.