Simplify the following text for a Grade 14 native English-speaking person.
Original: Until his victory in the Open Championship in 2009 , 2004 was his career year to date , with a fifth-place finish on the money list and wins at the MCI Heritage and at the WGC-NEC Invitational , which is one of the World Golf Championships events and was the most prestigious win of his career at the time .
Simplified: Until his victory in the Open Championship in 2009 , 2004 was his most successful season , with a fifth-place finish on the money list and wins at the MCI Heritage and at the WGC-NEC Invitational , which is one of the World Golf Championships events .