Guzan denied Samba again two minutes later, beating clear his bending, 12-yard strike to keep the scoreline at 0-0.
However, it did not remain that way for long. Villa lost possession inside their own half and QPR punished them dearly through Jermaine Jenas, who bundled the ball past Guzan after he had spilled Bobby Zamora's initial effort.
Harry Redknapp's side were by far the better team, but it was Villa who landed the next blow. Agbonlahor struck from close range in first-half stoppage time to make it level at the break.