"Grab is very clear. We are battle-tested. We have fought much bigger competitors ... We fought Uber tooth and nail. They were much bigger and they still are bigger than us globally," said Anthony Tan, group CEO and co-founder of Grab, which offers services in ride-hailing, digital payments and food delivery.
"We have shown every time we can rise above the challenge. Now, we believe competition makes us stronger," Tan told CNBC at the annual Innovfest Unbound conference in Singapore.
In March, Uber said it was selling its Southeast Asia business to Grab. That strengthened Grab's position in the individual markets across the region.
Tan's comments came on the back of an announcement in May by massively popular ride-hailing start-up Go-Jek that it was moving into four new markets in Vietnam, Thailand, Singapore and the Philippines, stepping up its rivalry with Grab.
The two start-ups already compete in Indonesia, where Grab is trying to establish a stronghold.
Grab has expanded well beyond its core ride-hailing technology, and is now involved in payments, bicycles and food delivery.
On Tuesday, Grab announced it would be launching what it called an "innovation arm" to support tech start-ups and promote technology in Southeast Asia.
—CNBC's Saheli Roy Choudhury contributed to this story.