The left-handed unseeded Indian put up a brave fight against his rival, ranked 96 places above him at 263, before losing 4-6 4-6 in one hour and 13 minutes.
It was the first singles semifinal appearance for Jeevan at a Challenger level event.
There was hardly any scope for error and when Jeevan blinked at 1-1 in the opening set, Buchanan made no mistake in getting that break. The Australian kept the lead with him and closed the first set in his favour as the remaining games went with serve. It was a good contest as Jevan played clean, fired five aces and made no double fault.
Jeevan will next play in an ITF event in Guam.