Mickelson in fine fettle in Scotland ahead of British Open bid

(CNN) -- Phil Mickelson warmed up for next week's British Open by mounting a serious challenge for the Scottish Open Saturday after a third round 65 at Castle Stuart.

The 42-year-old American opened with a disappointing one-over 73 but has charged through the field by playing the next two rounds in 15-under-par.

But in joint fifth, he still trails leader Francesco Molinari of Italy by three shots going into the final round at the links course in Inverness.

Four-time major winner Mickelson got a late invitation to compete in the European Tour event to complete final preparations for Royal Lytham and St Annes next week.

"I should have had it planned out originally, but there was a chance to take the kids to Italy," he told gathered reporters.

"I'm very pleased and excited. This course is so good at getting you ready for playing links golf. It does not beat you up so much."

Among the players he passed on the way was world number one and defending champion Luke Donald of England, who is a shot further back.

Mickelson finished joint runner-up to Darren Clarke of Northern Ireland at Sandwich last year and is still looking to lift the Claret Jug for the first time, having played the British Open every year since 1991.

Molinari carded a 67 to reach 17-under-par, one shot clear of Dane Anders Hansen.

He is bidding to emulate his brother Edoardo, who took the Scottish Open two years ago, but is sidelined by injury.

If he achieves his goal it would only be the second time in European Tour history that brothers had won the same tournament.

Spaniards Antonio and German Garrido took the Madrid Open title in 1977 and 1973 respectively.

Scotland's Marc Warren and Soren Kjeldsen of Denmark are joint third only two back.

Alex Noren of Sweden shared the halfway lead with Molinari and they were still together at the turn, but he dropped shots coming home to fall back into a tie with Mickelson, in a group which also includes American-based Scot Martin Laird and another home hope Peter Whiteford.

Laird, bidding to make the European Ryder Cup team, moved into contention with an eight-under 64 in benign conditions.