Southend ran out comfortable winners over Chesterfield to leapfrog them into fourth in League Two.
The hosts went in front when Luke O'Neill's cross-field pass set Anthony Straker in the clear, who in turn squared for Kevan Hurst to tap in.
Two goals in two minutes sealed the game for the Shrimpers when Ryan Leonard rounded Tommy Lee to slot in before Barry Corr's lobbed effort.
Chesterfield's Marc Richards then had a penalty saved by Daniel Bentley.
Richards had the chance to score from the spot when Gary Roberts was pushed by Hurst, but his miss compounded their misery.
VIEW FROM THE DRESSING ROOM
Southend United manager Phil Brown told BBC Essex:
"I think it was a great, great result. We were standing up to everything they threw at us.
"The whole team performed well today and none more so than Dan Bentley, who stood up to a barrage of efforts when we, in effect, had seen the game off.
"We are proving to ourselves that we can match anybody, so long as we are in the right frame of mind.
"What the players have shown today is how focused they were on beating Chesterfield. We can now enjoy the moment and get back to it next week."
Southend United 17 Bentley 32 O'Neill (Thompson - 44' Booked ) 03 Coker 18 Leonard 05 Phillips 06 Prosser 12 Atkinson 08 Timlin (Eastwood - 80' ) 10 Corr 14 Hurst 11 Straker (Woodrow - 74' ) Substitutes 01 Smith 04 Laird 07 Eastwood 16 Clifford 21 Payne 23 Thompson 33 Woodrow Chesterfield 01 Lee 25 Talbot 03 Smith 12 Ryan Booked 23 Evatt Booked 06 Cooper Booked 10 O'Shea (Gnanduillet - 57' ) 05 Morsy Booked 09 Richards (Doyle - 74' ) 02 Banks (Gardner - 64' ) 11 Roberts Substitutes 04 Hird 15 Humphreys 17 Doyle 21 Gnanduillet 22 Brown 26 Gardner 35 Dunbavin
Ref: Robert Madley