Middlesex 157 and 86 for 3 need 356 more runs to beat Derbyshire 265 and 333 for 3 dec (Reece 157*, Slater 99, Madsen 52)
Derbyshire are poised to end their long wait for a home Championship victory after they outplayed Middlesex for the third day running in the Division Two match at Derby.
Their chances were even slimmer after Sam Robson, Rob White and Hilton Cartwright were dismissed leaving Middlesex on 86 for 3 at the close and Derbyshire scenting a first home win since they beat Leicestershire at Derby in September 2014.
Derbyshire started the day in a strong position with a lead of 226 and they increased that by 53 in 17 overs before rain resulted in an early lunch.
Middlesex were without injured pace bowlers Toby Roland-Jones and James Harris and although they did well to restrict Derbyshire's run rate, it was always a question of when the home side pulled out.
Reece and Slater passed Derbyshire's previous highest opening stand against Middlesex of 181 and then eclipsed the best ever partnership against the county of 209 set in 1932.
Both looked certain to reach three figures but after Reece completed his third Championship hundred for Derbyshire from 268 balls, Slater became becalmed on 99 and cut a long hop from Ollie Rayner to cover.
Reece drove Rayner for six as he and Wayne Madsen added 101 before Paul Stirling had Madsen caught at short fine leg and Alex Hughes stumped before the declaration came leaving Middlesex to equal the highest winning fourth innings total against Derbyshire.
But their first target was to get through 29 overs against an attack that bowled them out for 157 in the first innings and although conditions were good for batting, Middlesex's chances suffered a big setback when Hardus Viljoen removed Robson.
The Middlesex captain played across a full length ball and was lbw for 5 and there was another breakthrough when Duanne Olivier replaced Viljoen at the City End. White shuffled across and was only half forward when he was struck in front and Olivier was celebrating again when he switched ends.
Hilton Cartwright pulled a short ball to the midwicket boundary but the next left him and took the outside edge to take Derbyshire a step closer to that elusive victory.