That's absolutely the closest you could come to a 59 without getting one. The PGA Tour commentators this morning have described Mickelson's round as a 59-and-three-quarters. But his 60 tied the course record with Kiwi former professional Grant Waite, who has left the playing ranks for a career in coaching.
And analyst and former top Kiwi professional Frank Nobilo summed it up beautifully; he said "In a way, this is so Phil, isn't it, in his career". Mickelson has never been the most consistent player out there; when he's hot, he's white-hot, but when he errs, he doesn't do it by halves.
Phil Mickelson will in all probability never have another put for a 59 in competition golf. The putt that lipped out yesterday was the golfing equivalent of the one that got away.