Freddy Eastwood's fourth goal in two games for Coventry dumped Plymouth to the foot of the Championship table.
Coventry forward ensures Mariner's first home game ends in defeat
Freddy Eastwood's fourth goal in two games for Coventry dumped Plymouth to the foot of the Championship table.
The striker, whose hat-trick had earned the Sky Blues a 3-2 victory over Peterborough last weekend, rose highest before heading David Bell's pin-point cross from the right wing beyond Romain Larrieu.
The result proved a baptism of fire for Argyle boss Paul Mariner, who was overseeing his first game at Home Park since taking the reins from Paul Sturrock.
With both sides toiling at the wrong end of the table, it was of little surprise they played out a low-key opening.
Plymouth's Jamie Mackie created the first half-chance after 23 minutes but his 12-yard effort was blocked by the imposing figure of Leon Barnett.
Chris Clark was next to try his luck for the home side just after the half-hour mark before the lively Eastwood rifled wide from 25 yards during a rare Coventry attack.
Alan Judge's weak free-kick drew a comfortable save from Keiren Westwood but it was the visitors who were unfortunate not to go in ahead at the half-time interval as Coleman's side spurned three chances in the space of as many minutes.
Michael McIndoe's close-range shot first struck Kari Arnason and Barnett failed to hit the target with the rebound. Leon Best then headed wide from McIndoe's left-footed free-kick with the goal seemingly at his mercy.
Missed chances
Westwood had to be alert eight minutes after the restart to parry Carl Fletcher's 20-yard strike.
The Pilgrims again went close to breaking the deadlock three minutes later as Rory Fallon rose well to meet another Judge set-piece but the New Zealand international planted his close-range header over.
Fallon, who scored the decisive goal to help the All Whites qualify for next year's World Cup, diverted another close-range header off target just after the hour mark from Shane Lowry's centre.
Judge continued to prove a threat from set-pieces but the home side were left to rue their profligacy as Eastwood broke the deadlock by nodding home with 18 minutes remaining.
Fallon had a goal-bound effort blocked by Elliott Ward as Plymouth battled to get back on level terms immediately before Bell hacked Lowry's header clear from a Craig Noone cross.
Westwood held his nerve to deny Fallon late on as Coventry clung on for the
three points.
