Fred Couples moved to within a stroke of Bernhard Langer at the Senior British Open on Saturday with a third-round 64 to the German's 66 to set up a final-round showdown between the two former US Masters champions.

''I'm just happy to be in the hunt with 18 holes to play,'' said Langer, who won this title two years ago at Carnoustie. ''There's a lot of guys in with a chance, so I know I'll have to shoot one of the lower scores to win.''

Langer is 7-under on 203, while Australian Peter Fowler (65) is a stroke behind Couples.

''It was a very, very good day,'' said Couples. ''Once I got going I didn't miss many shots. I hit my irons solid and when I hit them close I made the putt.''

Americans John Cook (66) and overnight leader Gary Hallberg (73) share fourth place at 3 under with England's Barry Lane (66).

On a day of low scoring by most of the leaders despite strong winds and squally showers, Langer and Couples both reached the turn in 30, trimming five strokes off par to overtake Hallberg, who shot 38 on the front nine.

Couples had birdies at Nos. 1, 3, 7, 8 and 9 while Langer birdied the first, fourth, sixth and ninth, eagled the long seventh and dropped a stroke at the fifth.

On the back nine Couples grabbed another two birdies and dropped one shot while Langer posted nine straight fours on the way home, bogeying both the par threes and getting a birdie on the long 17th.

Hallberg, leading Langer and Tom Lehman by three overnight, lost his advantage early by dropping a shot at three of the first four holes on his way to a 73, a score matched by his playing partner Lehman, who slipped down to level par alongside Tom Watson.

Watson's fourth British Senior title is probably out of reach, but the Turnberry specialist shot a 4-under 66 after a double-bogey six at the first when he found a fairway bunker off the tee, then took three putts.