Plymouth Argyle suffered their latest heavy away Championship defeat as Wayne Rooney lost his first managerial duel with old England team-mate Frank Lampard's Coventry City.

All the Sky Blues' goals came before the break against injury-ravaged Argyle, beginning with Tatsuhiro Sakamoto's early strike.

Recalled Josh Eccles made it 2-0 after 20 minutes, then City effectively ended it as a real contest with two strikes in six minutes just before the half-time interval.

In-form Ephron Mason-Clark scored his fourth goal in the six games since Lampard arrived - and there was still time for Eccles to add his second and City's fourth, tripling his tally for the season in the process.

Lampard's third win as Sky Blues boss lifts Coventry to 14th - 10 points off a play-off place.

Although bottom club Plymouth remain just two points adrift of safety, this was their fourth straight away defeat in a month to the tune of one goal scored and 16 conceded, having shipped six at Norwich City, four at Bristol City and two at Sheffield United.

To add to Rooney's woes, Plymouth had Callum Wright sent off in the 87th minute for a foul on Joel Latibeaudiere.

With so many attacking options all injured - Ryan Hardie, Michael Obafemi, Ibrahim Cissoko, Muhamed Tijani and Morgan Whittaker - Argyle boss Rooney was forced to give 16-year-old Tegan Finn his first start, following one appearance as a second-half substitute in the 3-0 defeat at Leeds in early November.

Rooney was also without skipper Joe Edwards, while Lampard could afford to make four changes from Saturday's 4-1 four-goal Callum Lang-inspired defeat at Portsmouth.

As well as bringing back goalkeeper Oliver Dovin after an eight-game absence for Brad Collins, he made three outfield alterations, giving recalls to defenders Jake Bidwell and Latibeaudiere and midfielder Eccles.

And, of all the changes, Eccles had the biggest impact, scoring twice either side of helping to create goal number three following Sakamoto's early opener.

It took just five minutes for Coventry to make the breakthrough when skipper Ben Sheaf floated a cross to the far post and Sakamoto stole in to head home.

On 20 minutes it was 2-0 when Mason-Clark latched onto a headed knockdown and laid off for Eccles to score with an excellent low finish.

But there was more to come as Coventry killed off the game with two goals in six minutes just before the break, immediately following Argyle's loss of injured midfielder Mustapha Bundu.

Eccles created the first of them for Mason-Clark on 39 minutes - and there was still time for a fourth after Jack Rudoni won the ball high up the field and, after Argyle could not clear their lines, Eccles again found the bottom corner.

Coventry are at home again on Sunday, with a quick return fixture against Millwall, who they beat at the start of December to earn Lampard's first win.

Rooney's Argyle remain on the road, with a trip to one of their fellow strugglers, 20th-placed Oxford United.