Lightning won 3-1 on home ice and completed the job with a stylish 4-1 success at Telford – Blaz Emersic (2) topped the scoring in their road win.
League champions Basingstoke Bison are through to the last four, courtesy of a 7-3 overall win against Manchester Phoenix.
Rene Jarolin grabbed the winner in a 2-1 road win and Bison followed up with a 5-2 success on home ice to keep their doubles hopes alive.
Last year’s winners Peterborough Phantoms progressed with a 9-6 aggregate win over Sheffield Steeldogs.
Phantoms triumphed 4-1 at Sheffield, but they were pushed hard in the reverse fixture as the Steeldogs claimed a 5-5 draw.
Guildford lost 2-1 at Swindon Wildcats in the first leg of their quarter-final, but two Danny Meyers goals in the return game sealed a 2-0 win for a 3-2 overall success.
Saturday – play-off quarter-final 1st leg
Manchester Phoenix 1-2 Basingstoke Bison
MK Lightning 3-1 Telford Tigers
Sheffield Steeldogs 1-4 Peterborough Phantoms
Swindon Wildcats 2-1 Guildford Flames
Sunday – play-off quarter-final 2nd leg
Basingstoke Bison 5-2 Manchester Phoenix (agg 7-3)
Guildford Flames 2-0 Swindon Wildcats (agg 3-2)
Peterborough Phantoms 5-5 Sheffield Steeldogs (agg 9-6)
Telford Tigers 1-4 MK Lightning (agg 2-7)
(Image permission: Tony Sargent)