Phil Mickelson at British Open 2015: Monday Leaderboard Score and Reaction

Phil Mickelson finished the 2015 British Open with a strong final round, but a disastrous triple-bogey on the 17th hole ended his chance to put himself in contention.

The 45-year-old hit six birdies as he recorded a three-under 69 in his best round of the competition, at one stage finding himself just two shots back on the leaders, before his round ended in catastrophic fashion.

The score leaves him nine shots behind leader Marc Leishman at seven under overall.

Here's the 2013 Open winner's scorecard, as well as the updated leaderboard:

Hole	1	2	3	4	5	6	7	8	9
Hole	10	11	12	13	14	15	16	17	18	Total
Par	4	4	4	4	5	4	4	3	4
Score	3	4	4	4	5	3	3	3	4
Par	4	3	4	4	5	4	4	4	4	72
Score	3	3	4	4	4	3	4	7	4	69

Speaking after Round 3, the five-time major winner believed he was close to finding his typically imperious form after a shaky start to the tournament, per Golf Digest's Alex Myers:

Mickelson looked to have found the final piece, as he began in bright fashion, birdieing the first hole in stark contrast to his bogey there on Sunday.

His excellent front nine continued, as he shot two more birdies at the sixth and seventh.

Fox Sports' Shane Bacon was full of praise for Mickelson—who teed off early due to starting the day on four under—for keeping the action exciting ahead of the battle between the leaders:

Another birdie at the 10th kicked off his back nine in style, with Golf Channel's Kelly Tilghman and the PGA Tour's official Twitter feed hinting that a real challenge for the Open was in the cards:

"

Phil Mickelson is climbing the board. Now -8, 4 back. Post early. Watch the weather. You never know...

— Kelly Tilghman (@KellyTilghmanGC) July 20, 2015"

The possibility of Mickelson putting himself in contention became a reality after another bout of consecutive birdies at the 14th and 15th, as the world's No. 21 ranked golfer showed real determination.

As Jeffrey Eisenband of ThePostGame noted, Mickelson was laying down the gauntlet for Dunne, Oosthuizen et al.:

The Guardian's golf correspondent, Ewan Murray, summed up a number of complaints on social media that fans in the UK were missing out due to the BBC's TV coverage starting midway through the round:

However, Mickelson's play ensured the BBC would show at least one "highlight" of his round on the 17th, when disaster struck.

SB Nation GIF shared the moment when Mickelson, on the verge of a stunning comeback, hooked his ball into a hotel balcony:

Jay Busbee of Yahoo Sports provided a comment from Mickelson about hitting the shot off the balcony had he been able to:

The ensuing triple-bogey swiftly ended his hopes of winning the 2015 Open, and Mickelson will now set his sights on the PGA Championship in August.

The 17th hole aside, he will take great encouragement from his excellent final day at St. Andrews. 

If he can maintain this form into the PGA, he will surely be in contention yet again.

For the British Open, the attention must now turn to Leishman and Jordan Spieth, one of whom could well make history with a win here.