UPDATE 2-Motor racing-Sacked Bourdais slams Toro Rosso F1 team

* Bourdais sacked, threatens legal action

* Teams says Frenchman did not meet expectations

* Spanish teenager Alguersuari expected to replace him (Adds Bourdais statement)

By Alan Baldwin

LONDON, July 16 (Reuters) - Spanish teenager Jaime Alguersuari is set to become Formula One's youngest ever driver after Toro Rosso sacked France's Sebastien Bourdais on Thursday.

The Ferrari-powered team, winners of their home Italian Grand Prix last year with Germany's Sebastian Vettel, said four-times Champ Car champion Bourdais had made his last appearance for them.

His replacement will be announced shortly before next week's Hungarian Grand Prix.

"In Sebastien's second year with us, the partnership has not met our expectations," added team boss Franz Tost. "Therefore we have decided to replace him as from the next round of the world championship."

Bourdais replied with an angry statement of his own, saying he was shocked by the team's actions and threatening legal action for breach of contract.