The last time Apple shares fell for eight consecutive sessions, the brightly coloured iMac was the firm’s hottest product.
But in recent days more than $73bn (£49.4bn) has been wiped off the iPhone-maker’s market value, with shares falling for the eighth straight session on Monday.
It follows Apple’s announcement last week that iPhone sales fell for the first time, while revenue was down for the first time since 2003.
Shares in Apple currently stand at $93.64 (£63.41) each – down from a high of $132.40 (£89.68) in May last year.
But when asked if Apple’s best days are behind it in a television interview, chief executive Tim Cook said: “I couldn’t disagree more”.
He said such claims were a “huge overreaction” and insisted that “the most important thing is that customers love our products”.
Mr Cook acknowledged that the global smartphone market is not growing, but says he is “very optimistic” that current issues will pass and Apple “shall grow again”.
Two-thirds of Apple’s revenue comes from the sale of iPhones, and the popularity of 2014’s iPhone 6 and 6 Plus means sales in 2015 and 2016 have paled in comparison.
Mr Cook said: “The iPhone 6 is an anomaly, and so it creates a very difficult comparison for us.”
He also denied that the Apple Watch had been a failure, saying: “We’re still in learning mode … you’ll see the Apple Watch get better and better.
“Our first goal is to establish a new category. We wanted to roll out slowly.
“The future of Apple is very bright, our future product pipeline has some amazing products.”