Villa, 31, suffered a broken leg midway through last season and appeared well below his peak form on his return.
The Spain forward’s travails extended into this season, but he has scored in his last two matches, with performances to match.
“There has been a change in David Villa, he is exuding a joy and optimism now,” Del Bosque said.
“He is happy with his form and we have regained the greatest goalscorer in the history of Spain’s national team.”
Villa has scored 53 goals in 86 appearances for Spain, with the highest goals-to-games ratio since Alfredo Di Stefano.