Credibility - That elusive thing

One of my friends, a lawyer with a mid size law firm, told me a story of a bid they made and eventually won with a large bank. After the bid, when he was talking to an insider about why they won, the reason given was, 

You guys admitted you could not do several things we wanted done. All others said they could do everything. Your statement matched your firm profile and size. Your story was believable. We felt your story had credibility. We decided to work with you and help you bridge your gaps in capability. 

You can win deals (and deliver successfully) if you can retain your credibility. Dream big certainly, but be careful not to trample on your credibility!