Beyoncé Knowles and Jay Z were reportedly ''all business'' as they wrapped up the US leg of their 'On The Run' tour in San Francisco on Wednesday night (06.08.14) amid rumours their marriage is ''crumbling.''

The couple, whose six-year marriage is allegedly ''crumbling,'' performed the last of their North American 'On The Run' concerts in San Francisco on Wednesday night (06.08.14), where their lack of chemistry on stage was reportedly ''palpable.'' A source told UsMagazine.com that the duo, who have two-year-old daughter Blue Ivy, also appeared ''very tired'' onstage at AT&T Park.

The eyewitness added: ''It was all business for these two. ''Beyonce's eyes on the screen looked red.'' But the couple put on a united front as they performed their latest hit, 'On The Run,' and the insider added: ''They gave each other a squeeze and a tickle. She still seemed unfazed and managed a smile before slipping away from him.'' Before leaving the stage, the 32-year-old singer ''held hands with Jay leading the way,'' as a home video, featuring their daughter, played on big screens around the packed stadium.

Sources previously claimed that the couple's business relationship is now more important to them than their marriage. But one pal recently insisted they are still committed to each other, saying: ''There's still something there, even though it's not going to last. Business is always part of the equation. They know they're the king and queen of hip-hop - and really, all of music. Neither wants to lose that. ''They are solid, solid business people who know what they're doing.''