Milton Keynes - Northampton lived up to their billing as favourites as they advanced to the semifinals of the European Cup on Sunday with a hard-fought 23-13 win over Ulster in Milton Keynes.
The only English side left in the competition joined Leinster and Perpignan in the final four with the last ticket being decided between French clubs Biarritz and Toulouse who play in San Sebastien later on Sunday.
Northampton had entered the quarterfinals as the top seeds being the only team unbeaten through the pool stages, but had to power back in the second half after trailing by three points at the break.
They next meet Perpignan who came away with a tight 29-25 victory over another French team Toulon in Barcelona on Saturday.
Saints got off to a blistering start, taking advantage of early Ulster nerves with Soane Tonga'uiha touching down a try after just four minutes.
The Tongan prop steamrollered his way down the middle and stretched his right arm over the line to slam down with Stephen Myler converting.
But Ulster launched a series of attacks which paid dividends with Andrew Trimble touching down a try which Ian Humphreys converted and another Humphreys penalty allowed the Irish to lead 13-10 at half-time.
A Myler penalty levelled proceedings 13-13 with half an hour to go and ten minutes later Saints were ahead when Lee Dickson scored the decisive try, which Myler converted to give Northampton a seven-point advantage.
A further Myler penalty put Northampton ten points ahead, as the flyhalf accounted for 13 of his side's points. Ulster fought for a late try but could not find their way past the hosts.
On Saturday, four Jonathan Sexton penalties and an Isa Nacewa try enabled Irish side Leinster to beat England's Leicester 17-10 at the Aviva Stadium to book a final four showdown with Biarritz or Toulouse later this month.