Premiership leaders Hearts are through to the last four of the Betfred Cup after beating Motherwell 4-2 at Tynecastle on Wednesday night.
Late goals from Olly Lee and Steven Naismith made the difference as Craig Levein's men continued their unbeaten start to the season. Steven MacLean and Peter Haring also scored for the Jam Tarts, with Curtis Main (penalty) and Ryan Bowman on target for the Steelmen.
Holders Celtic defeated St Johnstone 1-0 at McDiarmid Park thanks to an 83rd-minute goal from Leigh Griffiths.
A double from Glenn Middleton and goals from Nikola Katic and Alfredo Morelos earned Rangers a 4-0 victory over Ayr United at Ibrox.