There's a good chance the British Open goes to a playoff in this second-ever Monday finish, and if it does, it'll extend an already long tournament even more.
The British Open playoff format isn't sudden death. Rather, it's a four-hole aggregate-score playoff, meaning that the competitors will play out the four holes and the lowest combined score will win the Claret Jug.
At St. Andrews, the playoff holes are Nos. 1, 2, 17 and 18. They're also the same holes used for the Wednesday Champions Challenge exhibition. If, after the four holes are played, any players are tied for the lead, then they'll transition to a sudden-death playoff to determine the British Open.
Since the R&A went to this aggregate-score playoff, it's been employed nine times. Marc Calcavecchia won the first four-hole playoff in 1989 for his lone major championship win.
The Home of Golf has been home to one prior four-hole playoff, with John Daly defeating Costantino Rocca in the 1995 Open 15-19 for his second major title.
Here are the other six four-hole playoffs in British Open history:
1998: Mark O'Meara def. Brian Watts at Royal Birkdale
1999: Paul Lawrie def. Jean van de Velde and Justin Leonard at Carnoustie
2002: Ernie Els def. Stuart Appleby, Thomas Bjorn and Thomas Levet at Muirfield
2004: Todd Hamilton def. Ernie Els at Royal Troon
2007: Padraig Harrington def. Sergio Garcia at Carnoustie
2009: Stuart Cink def. Tom Watson at Turnberry