It just worked for DH. He had an offer from #2 and #1 called to moved his 4th!! interview 2 weeks later, instead of the next day. He told them about the offer from #2 and they called him back with their own offer 15 mins later and managed to do all his reference checking and get the offer in writing within 24 hrs.
There were also other employers he tried this with and they decided not to hire him. It certainly cant hurt if you do it the right way.