Former Education and Welfare officer Lucy Ward told the tribunal she was "bewildered" at being dismissed after returning from BBC commentary duty at the 2015 Women's World Cup.
Ms Ward, the partner of ex-Leeds United head coach Neil Redfearn, claims unfair dismissal and sex discrimination.
The club denies any improper conduct.
Leeds United insist Ms Ward, an employee of 17 years, was dismissed for exceeding her annual leave entitlement.
The tribunal in Leeds heard from Ismail Ghandour, a businessman who met with former club chief executive Adam Pearson last year about the possibility of using his contacts to bring in investors to the club.
At that point, Mr Ghandour said, coach Mr Redfearn was either "on gardening leave or on his way out".
He told Mr Pearson he had heard "rumours on Twitter" about Ms Ward's future at the club, so asked him if they were true.
Mr Ghandour was told chairman Massimo Cellino saw Neil and Lucy "as a pair", the hearing learned.
When cross-examined by Leeds United's barrister Lucy Bairstow, Mr Ghandour said he was friends with Mr Redfearn and Ms Ward and "everybody knew" the pair were in a relationship.
Ms Ward told the tribunal she was alerted by a colleague about the locks on the doors to her work office being changed while she was away on leave.
After returning from Canada, she said she was told by Mr Pearson "I was suspended and there was a letter in the post".
She said: "I went into the disciplinary thinking I was going to have a fair disciplinary process.
"It was quite bewildering as a committed, loyal member of staff to be treated like that."
Ms Ward said she thought Mr Pearson would be more honourable than simply to follow through someone else's wishes "because of my relationship with Neil".
She told the hearing she warned her line manager about her trip for BBC work and said the club bosses "treated me differently to every other member of staff who behaved similarly".
The three-day tribunal is due to continue on Tuesday.
Leeds United's chairman sacked an employee because she and the head coach he planned to lose came as "a pair", an industrial tribunal heard.