Lowry entered the day with a four-stroke lead. He shot 1-over 72 and finished with a 15-under 269 total. It was the second time Lowry went into the final round of a major with a four-stroke lead, but he ended up in a tie for second at the 2016 U.S. Open after shooting a 6-over 76.
There was never any major scare on Sunday at the first British Open in Northern Ireland since 1951. Fleetwood got within three strokes after the first hole but never got any closer, finishing with a 3-over 74.
British Open leader Shane Lowry has increased his lead to five strokes at the turn in the final round.
Lowry started the day with a four-stroke lead over playing partner Tommy Fleetwood but dropped a shot on the first hole of the day. He rebounded with birdies on Nos. 4, 5 and 7 before bogeys on 8 and 9 put him back at 16 under overall after nine holes.
Fleetwood, who briefly closed the deficit to three strokes early in the round, is at 11 under overall and 1 over on the day with nine holes to go.
Shane Lowry's lead that dropped to three shots with a bogey at the start is now double that margin as he approaches the turn, six clear of Tommy Fleetwood.
Out of the mix is four-time major champion Brooks Koepka, who had a steady stream of mistakes. Koepka needed to charge and instead bogeyed the first four holes. He stopped the slide with an eagle on downwind par-4 fifth hole and settled into pars the rest of the way.
Rickie Fowler hit his first shot off a marshal and out-of-bounds. J.B. Holmes also went out-of-bounds on his first tee shot.
This is Lowry's show.
British Open leader Shane Lowry has teed off in the final round.
The Irishman, greeted by loud cheers as he was introduced, was the last player in the field to begin the last round of the tournament at Royal Portrush. He leads at 16 under, four strokes ahead of Tommy Fleetwood — his playing partner on Sunday.
Lowry shot 8-under 63 in the third round to give him the 54-hole record in the British Open at 197.
Ashton Turner is the first player to complete 72 holes of the British Open, not necessarily a badge of honor because he was in last place going into Sunday. He made the most of it and beat the bad weather with a 3-under 68.
There already have been periods of light rain as weather figures to be a big part of the final round. The forecast was for heavy rain at times and gusts approaching 40 mph. It was severe enough for the R&A to move forward the starting times by one hour.
Shane Lowry, with a four-shot lead, won the Irish Open as an amateur 10 years ago in nasty weather. He doesn't figure to have a big advantage, though. He is playing with Tommy Fleetwood of Southport, England, which gets its share of bad weather.
Shane Lowry of Ireland is one round away from capturing the British Open, and he's not afraid to think about what it could mean.
Lowry is coming off the best day of his career when he shot 8-under 63 before a raucous gallery at Royal Portrush. He set the 54-hole tournament record and built a four-shot lead over Tommy Fleetwood.
Expectations are high, and Lowry is embracing them. He says it's natural to consider what's at stake, and the more he tries not to think about it only means he'll think about it more.
It might be best to look forward. In the last 20 years, only four players have lost a 54-hole lead of four shots or more.
One of them was Lowry in the 2016. U.S. Open.
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