 Complete the following phrase:  He reached his first world final in 2001, where he defeated John Higgins 1814 to claim his first world title and reach number two in the world rankings. He won his third UK title later in 2001, which helped him attain the world number one ranking for the first time in the a hrefSnooker20world20rankings202002200320022003 seasona. With veteran six-time world champion Ray Reardon acting as his coach and mentor, he won his second world title in 2004, defeating Graeme Dott 188 in the final, after which he held the number one ranking for the next two seasons. He added his second Masters title in 2005, ten years after his first. However, his behaviour became notably erratic in the mid-2000s as he battled clinical depression. During the 