Jason Day is joint-top of the leaderboard with Scott Piercy at the WGC-Bridgestone Invitational thanks to a third round one-under 69.

The Australian world number one held a slender one-shot advantage going into Saturday's play at the Firestone Country Club in Ohio, but he looked set to be usurped when he fired successive bogeys at the end of the front nine.

But Day recovered with an impressive 35-foot eagle on the 15th to ensure he will start Sunday's final round still leading the way.

Despite a disappointing overall round, in which he managed to find only three fairways, Day is confident of winning the tournament.

He told worldgolfchampionships.com: "I hit some pretty errant shots out there, but the short game saved me.

"I was just trying to play the draw and there was a section in my round where I just kept on losing everything right and getting myself into some trouble.

"There are a lot of negatives you can look at this round with regards to my hitting, but the positive is that I am still tied for the lead and have not hit the ball well all week.

"If I can hit it anywhere sort of decent tomorrow, give myself a few more opportunities on the green, I feel I have a really good chance of winning."

American Piercy, who finished tied for second at last month's US Open, fired an eagle at the second hole in a three-under-par round of 67.

A bogey at the 18th hole denied him the opportunity to go into the final round leading the way by one shot.

Sweden's David Lingmerth fired a 69 to sit in third place on four under for the tournament, while American Brian Stuard is a shot further back.

US Open champion Dustin Johnson hauled himself into contention with a best-of-the-day 66 to move up to joint-fifth, three shots off the leaders.0