The Australian press used the term 'Warrenball' to describe the way that Gatland's British and Irish Lions side played as they secured a series win over Australia last summer.
O'Connell, who was part of the Lions team that successfully toured Down Under, believes that Gatland deserves more credit.
"I think it's a bit of an unfair tag, obviously because they're big men you just think their game's all about physicality," O'Connell told BBC Sport.
"But there's an incredible amount of subtlety to what they do as well. I remember seeing that in the last two tours."
Gatland was appointed Wales coach in 2007.