Three goals in the last 11 minutes condemned Reds to a 3-2 defeat against Chelsea under-21s in their final pre-season friendly at the Checkatrade.com Stadium.
The home side were in control at half-time thanks to a terrific volley from Josh Simpson and Izale McLeod’s low finish.
John Gregory changed the entire team during the second half and Crawley struggled to maintain their superiority and after Patrick Bamford had hit the post they struck three times to stun the home fans.
Ola Aina headed their first, fellow sub Charlie Colkett levelled two minutes later from a free-kick and four minutes from time Charly Musonda beat substitute keeper Raphael Spiegel with a speculative effort from distance.
John Gregory started with what could be the team that lines up at Oakwell next Saturday in our League One opener. He named 12 subs including 21-year-old Canadian midfield trialist Austin Dias.
Reds threatened first after three minutes when Gavin Tomlin slid a pass into the path of McLeod, but his left-foot shot lacked sufficient power and Bradley Collins made the save.
The Chelsea side included players with Championship and League One experience and it was a familiar foe who was soon threatening Reds.
Bamford scored on his last visit to Crawley on Boxing Day for MK Dons before linking up with Derby County for the second half of last season. On five minutes he dispossessed Dean Leacock and went for a chip that flew over.
Bamford had two more efforts which were safely held by Brian Jensen, who was also tested from long range by Kasey Palmer and George Saville as Chelsea enjoyed a good spell.
Back came Reds and Lewis Young got on the end of Gwion Edwards’ cross but volleyed wide before Collins was pleased to see Jimmy Smith’s effort from 30 yards against his former club drift inches wide of the post.
But Collins had no chance when Reds took the lead on 34 minutes. Man of the match Ryan Dickson’s deep cross from the left was headed back across goal by Leacock and Simpson reacted quickest to volley home from 10 yards.
Reds doubled their lead a minute before the break. McLeod showed great strength to hold off his marker and beat Collins with a low drive from the edge of the box.
Within seven minutes of the re-start Reds had made four changes with Spiegel, Emmett O’Connor, Conor Henderson and trialist Charles Banya coming on for Jensen, Simpson, McLeod and Tomlin.
Edwards wasn’t far away from extending Reds lead when he cut inside but fired into the side netting from the edge of the box.
Reds then made another raft of changes which included a debut for on-loan midfielder Mitchell Rose and more alterations halfway through the second period meant the entire side had changed with 15 minutes to go.
With so many changes by both sides the game now lacked shape and pattern although Chelsea should have pulled one back on 66 minutes when Alex Kiwomya shot wide from close range. They went even closer five minutes later when Bamford’s side-footer from the right came back off the inside of the post.
As the game entered the last 15 minutes Chelsea had got on top and were level with two goals inside two minutes.
They reduced the deficit with 11 minutes to go when Aina rose highest to get onto a free kick by Colkett and give Spiegel no chance with his header.
Spiegel was beaten again a minute later when Colkett fired a free kick into the bottom corner from 25 yards after Alex Kiwoyma had been brought down.
And it was to get worse for Spiegel, who was beaten by a speculative effort from distance by a third Chelsea sub Musonda in the 86th minute.
Reds: Jensen (Spiegel 45), Oyebanjo (Bawling 63), Dickson (Adamatey 77), Leacock (Bradley 60), Walsh (Stewart 60); Edwards, Smith (Rose 63), Simpson (Henderson 45), Young; McLeod (O’Connor 48), Tomlin (Rose 52).