Winger Isgrove was substituted at half-time at Oakwell, but still played a key role in the Tykes’ victory, with his surging run forcing a tenth-minute corner from which the hosts opened the scoring, as Marc Roberts headed in Conor Hourihane’s delivery.
Stephens played the full game at centre half for Coventry, continuing his partnership with Baily Cargill at the heart of defence, but the City back line was breached for a second time when Ashley Fletcher converted from close range on the hour mark, after Hourihane’s left-wing free-kick had resulted in a scramble inside the area.
The result means Barnsley have moved up to seventh, and are now behind Coventry, who occupy the final play-off spot, only on goal difference.
Elsewhere in League 1, centre back Jordan Turnbull helped Swindon Town to a clean sheet and a fourth consecutive victory, as they triumphed 2-0 at home to Doncaster Rovers.
A goal in either half from Jonathan Obika ensured the Robins took maximum points, while the visitors ended the night with ten men after former Saints player Richard Chaplow was sent off late on for two yellow cards.
Town’s good run has seen them climb to 11th in the table, just four points behind the play-off positions.
Sam McQueen started for Southend United as they also kept in touch with the top six, thanks to a late equaliser in a 1-1 home draw with Crewe Alexandra.
The forward lasted 58 minutes before being substituted, with the score still 0-0 at that stage.
Drama ensued in the final four minutes, as Crewe snatched the lead through George Cooper’s curling free-kick, only for the Shrimpers to rescue a point in added time when Jack Payne converted from the spot after Ben Nugent had fouled Jamar Loza.
McQueen’s Southend are now eighth in League 1, but are just one point behind Isgrove’s Barnsley and Stephens’ Coventry in the two positions immediately above them.
In League 2, defender Jason McCarthy played the full game for Wycombe Wanderers, but could not prevent them losing 1-0 at Cambridge United and dropping out of the play-off spots.
The Chairboys slipped three places, to ninth, but remain just one point outside the top seven, after Josh Coulson’s deflected header on 28 minutes proved enough for the hosts to take all three points.
In the Championship, Gastón Ramírez came on during the second half for Middlesbrough and set up a goal, but could not prevent their automatic promotion hopes being dealt a blow in a 2-1 defeat at Blackburn Rovers.
By the time Ramírez was introduced in the 64th minute, Boro already trailed 1-0 through a Hope Akpan header, and Danny Graham effectively sealed the points for the home side with seven minutes left with a deft finish to make it 2-0.
The visitors pulled one back at the start of added time, as Ramírez laid the ball into the path of Adam Forshaw, who strode forward and struck into the bottom corner from the edge of the area, but Boro could not find an equaliser.
The result ended a five-match unbeaten run for the side and means they stay third in the table, missing out on the chance to overhaul leaders Burnley and Hull.