Wyatt scaled new heights with an outstanding run at Crans-Montana, covering the 12km race, which ascended 1046m, in 55 minutes 03 seconds, to beat Martin Toroitich of Uganda by 13sec.
Ahmet Arslan of Turkey was some distance behind third, in a time of 55min 26sec.
Wyatt won his previous titles in 1998, 2000, 2002, 2004 and 2005.
He didn't compete last year and was narrowly beaten in 2006 after a dog bite incident in training two days before the event.
New Zealand's Callum Harland was 69th in 1hr 2min 04ssec and Glenn Hughes 74th in 1hr 2min 23sec.
Anna Frost was 10th in the women's 8.33km race, which ascended 733m, in 47min 35sec.
Andrea Mayr of Austria won in 43min 57sec.
Daniel Jones, 17, was 22nd in the junior men's race over the same distance in 44min 50sec.
A record number of 39 countries sent athletes to what will be the last world championship trophy race.
The International Association of Athletics Federation Council has determined that from next year there will be a mountain running championship series.
