Burghardt caught solo escapee Carlos Barredo 94km into the 197km stage and held off the Spaniard’s late dash in the closing metres to secure Team Columbia’s fifth stage win of the Tour.
The 25-year-old German had the chance to put last year’s mishap with a canine onlooker behind him on an uneventful day.
After three tough days in the Alps, the main contenders were content to conserve their energy for the crucial time-trial from Cerilly to St Amand Montrond on Saturday.
Carlos Sastre came through unscathed and retains his 84-second lead over CSC colleague Frank Schleck.
Sastre, hoping to become the third consecutive Spaniard to win the Tour de France after Oscar Pereiro and Alberto Contador, must decide whether to try and gain more time on Cadel Evans in tomorrow’s flat stage from Roanne to Montlucon.
Sastre still heads Evans by 94 seconds in the race for outright victory, but with a long, 53km stage against the clock to come.
The Australian is a vastly superior time-triallist, though Sastre has made genuine attempts to improve his aerodynamic position in recent years.
In the shorter 29.5km time-trial at Cholet in stage four, Sastre still conceded 70 seconds to Evans.
The situation is eerily similar to 1989, when Greg LeMond turned a 50-second deficit on Laurent Fignon into an eight-second win in the closing time-trial from Versailles to Paris.
The only major gains in yesterday’s Massif Central stage were made by Andy Schleck and Roman Kreuziger, who came in 11 seconds ahead of the groupe maillot jaune and edged closer to the top 10.
Burghardt shrugged off Barredo’s attempts to toy with him on the Cote de Sorbiers and then again when they reached St Etienne.
Further back, Damiano Cunego, Philippe Gilbert and Alexandre Botcharov suffered a nasty crash 33km into the stage.
Medics applied treatment to Cunego’s chin and he rejoined in a group detached from the yellow jersey. In the race for the other jerseys, Oscar Freire made more gains on sprint rival Thor Hushovd, giving him a 49-point lead in the points competition with the traditional sprint up the Champs-Elysees to come.
Barring accident or withdrawal, Bernhard Kohl will be the first Austrian to win the polka dot jersey for the King of the Mountains competition.
The prospect of a genuine opponent for Kohl ended after injury to 2007 winner Juan Mauricio Soler, and the withdrawal of Saunier Duval-Scott climbers Riccardo Ricco, David de la Fuente, Leonardo Piepoli and Juan Jose Cobo.
During the stage, French customs officials searched a car belonging to Johnny Schleck, the father of Frank and Andy.
The inspection, which found nothing untoward, was part of a series of random checks near Grenoble.