Mr. Santorum's few advisers said he must focus on the "deeply patriotic working-class family whose outings might include Cracker Barrel and Starbucks, " said Mark Rodgers, his former chief of staff.

WSJ: On the Road With Rick Santorum as He Takes Spotlight, Tests GOP

The final decision was made Monday night, while the candidate's family was on the phone with senior strategists John Brabender, longtime adviser Mark Rodgers, campaign manager Mike Biundo and just a few others, the source said.

CNN: Santorum suspends campaign, clearing Romney's path

During the winter Chambers had already set a season-best mark of 6.51s, equalling the time of American Michael Rodgers, and he was a huge favourite for Sunday's final.

BBC: Chambers storms to gold in Turin