Woods and Westwood paired in Akron

Tiger Woods and Lee Westwood go head to head with the world number one spot at stake when the WGC-Bridgestone Invitational starts in Akron, Ohio, on Thursday.

Defending champion Woods – he has won at Firestone on his last four trips and a US Tour record seven times in all – is under threat from both Westwood and Phil Mickelson at the top of the world rankings.

Woods and Westwood were playing partners in the first two rounds of the Open last year, with Westwood outscoring the American by seven and going on to finish third while Woods missed the cut.

They tee off at 1.50pm local time (6.50pm Irish time) just ahead of Padraig Harrington and US Open champion Graeme McDowell, who were also partners on the opening two days of the Irish Open last week.

Mickelson plays with Rory McIlroy, who pushed him into second place with a dazzling finish to the Quail Hollow Championship in May.

They are among the early starters, teeing off at 9.50am (2.50pm Irish time).

Mickelson could reach the number one spot for the first time with a top-four finish providing Woods is well down the field, but if he wins the tournament there is nothing Woods can do to prevent the end of his latest five-year reign.

Westwood, runner-up in the Masters and Open this season, has to finish first or second just to have a chance of overtaking the two Americans.