Is it a competency based interview?
If yes do you know what the competencies are and have you got good solid examples you could use for all of them?
For example if the competency is 'Be agile' do you have an example of a preferably recent time you adjusted to meet an urgent need, reprioritised, delegated etc.
Can you deliver that in the STAR format (Situation, task, action, result)
'I was working through my list of BAU activities when I was notified that a team member would be unable to attend work and had a presentation that was due to be delivered to an important client that day. I agreed to take on the presentation as I was aware of the urgency and importance of the task. I went through my list and prioritised activities that needed to be completed that day and identified which of those I could realistically complete. I approached my colleagues and explained the situation, then chi of my colleagues would be able to support my tasks based on their skill level and available time. I clearly explained what needed to be done, the time expectation, provided reference material where needed and established a check in point to make sure those activities progressed.
I then reviewed the presentation and familiarised myself with the material. I confirmed my understanding of any areas I was less familiar with.
I delivered the presentation receiving positive feedback from both the client and my line manager. My colleagues were able to complete the activities assigned to them and I completed the remainder of the high priority items that day and the rest of the list the next day which remained within SLA.
I made sure to express my appreciation to the team, as they supported my ability to be flexible in this situation'.
If you hit all the points and if the interview is scored, then in theory you have the ability to be successful even over someone who is already in post.