After scoring a 35-20 victory away to Worcester Warriors, Tigers' progress was confirmed two hours or so later when Newport-Gwent Dragons beat Northampton Saints in the other Group C fixture without either side picking up a bonus point. That gave Tigers 10 points from two games and an unassailable lead in the pool.
Pat Howard acknowledged a good team performance at Worcester, where the tries were scored by Daryl Gibson (2), Sam Vesty and James Buckland.
"We came with the aim of scoring a bonus point," said Howard, "and we played pretty well. Jordan Crane and Sam Vesty played really well, Louis Deacon did very well in the nitty-gritty stuff, Lewis Moody worked hard, Paul Burke controlled the game very well for the first 40 minutes or so, Ollie Smith is coming back to form, Daryl Gibsn got two tries, so a lot of guys did very well.
"The work in the tight was really pleasing, while we also passed the ball around and looked to spread the play.
"We got off to a nice start with an early try, similar to the win at Harlequins a couple of week ago, and we also missed a couple of scoring opportunities which would have put some distance in it. But we kept our composure and that's good to see."
Deacon was among those to pick up knocks, while Burke limped off with a knee injury and Ben Kay suffered a back injury which forced his withdrawal early in the second half.