The Rams were in deep trouble when Simon Ainley and Neil Crosland took four wickets apiece to leave them on 121 for nine.
That brought Dean to the crease and he and fellow experienced player Neil Eastwood changed the complexion of the game with an unbroken stand of 81.
Dean hit three sixes and four fours in an unbeaten 46 while Eastwood helped boost the total to 202 for nine with 29 not out.
Eastwood followed up with six for 15 as demoralised Outlane were shattered for 51 in just 14.1 overs, Dean also turning his arm with his sole over going for just two runs.
In the Premier Division, 15-year-old Kieran Rodger kept Triangle flying high with a six-wicket haul as visitors Blackley subsided from a promising 132 for three to 185 all out.
An unbeaten 56 from Shaun Charnley wrapped up a four-wicket wicket win for the hosts.
In Division One, an amazing late assault from under 17s player Junaid Rashid helped Warley snatch a one-wicket win at Sowerby St Peters.
Warley looked out of it with their overs running out at 174 for nine, chasing 215 for victory. That was in spite of long-serving number three Andrew Oates still being at the crease, having come in when opener Ben Atkinson was bowled first ball after back-to-back centuries.
Oates had never seen Rashid bat before and looked on in amazement as the left-handed youngster opened his shoulders and crashed four sixes, finishing the match with a straight hit into the sightscreen.
Oates, who finished on 94 not out, said: “Without those heroics we wouldn’t have won. We needed 22 off the last two overs and won with four balls to spare!”
Earlier, another teenager, Shezad Hassan had taken four for 31 including the wicket of opener Adam Clarke - younger brother of first team skipper Gavin - for 76.
BLACKLEY have claimed the final place in Sunday’s line-up for the quarter finals of the Crossley Shield, beating visitors Clayton by 63 runs in a delayed second round game.
Steve Ashton followed up his 85 at Triangle on Saturday with his side’s top score of 70 and then took three catches.
A sixth-wicket stand of 108 between ex-Triangle player John Dean (68) and Bilal Sheraz (62 no) helped Blackley to 314 for six and that was too many for Clayton in spite of 72 from Andrew Sutcliffe.