Judge Pavel Kardyni scored the contest 116-112, Donald Trella 117-111 and Mickey Vann 118-110. Randy Neumann of America officiated.
Pulev, the world amateur bronze medallist in 2005, had looked impressive in stopping both Alexander Ustinov and Alexander Dimitrenko in the 11th round of their respective fights in 2012, but against the cagey Thompson in the early going he was reluctant to let his hands go as the visitor jabbed to both head and body.
Thompson came into the contest just seven weeks after inflicting the second defeat on Liverpool’s David Price and for four rounds his educated jab looked to be the weapon that would take the unbeaten record of Pulev too.
Thompson looked relaxed boxing at a slow pace behind his jab until Pulev finally threw caution to the wind and let his hands go in round five as a counter right landed on the chin of the American with a follow up left just missing by millimetres.
Thompson retreated to the ropes in round six, an invitation for the champion to unload a three punch combination, and Pulev secured the session with a chopping right hand.
Thompson complained about a punch that strayed around the back of his head but he couldn’t complain about the left hand that snapped his head back moments later. Pulev had sharpened up and suddenly come to life as Thompson visibly slowed.
Both men traded clubbing blows in round eight but the action soon became sloppy as referee Randy Neumann was forced to split them on several occasions.
Two straight rights followed by a left from Pulev clattered off the chin of Thompson in round nine as Thompson’s success rate began to drop and the American suddenly looked all of his 41 years during a dominant session for the champion.
Pulev had Thompson on the canvas late in the round but it was ruled a slip.
Thompson resorted to pot shotting as he tired in round 10 and it was clear he would need a knockout to claim another unbeaten fighter’s scalp. Pulev made sure of victory in rounds 11 and 12 and cruised home to a comfortable point’s victory.
Thompson falls to 38-4 (26).