"He says, 'I wanted to prove something to you. A lot of putting nowadays is very technical and mechanical—you have to have the right length putter with the right lie and the right loft. That thing [the 5-wood] has 19 degrees [of loft] and is about 10 inches too long and you've just holed three in a row. That's what you need to get back to. It needs to be instinctive,' " McIlroy said. "And it was such a massive flip. We had that one session on Monday afternoon and I went to Bay Hill and had the best putting week of my career."