Gilmour was a stand-out performer in midfield and fellow rookies James and Marc Guehi also impressed, while there was a welcome return for England winger Hudson-Odoi, his first appearance since picking up an Achilles injury in April.

Making 11 changes may have been a risk for Lampard, certainly given the events of 24 hours earlier.

But a repeat of Tottenham's shock defeat by Colchester, who lie level on points with Grimsby, did not look on the cards after Chelsea raced into a two-goal lead.

With just four minutes on the clock Barkley collected Pedro's pass 25 yards out and powered past Town midfielder Harry Clifton into the area before firing low inside James McKeown's near post.

Three minutes later it was two, Batshuayi spinning in the area before lashing the ball home.

But Grimsby, who lie 66 places below Chelsea, stunned the Blues when veteran Matt Green halved the deficit with a spectacular long-range effort.

To their credit Grimsby more than held their own for the rest of the first half until, in the 43rd minute, Green tugged Zouma to the ground at a corner to concede a penalty.

Barkley had insisted he would take Chelsea's next spot-kick despite his miss against Valencia, but evidently not. At least there were no arguments this time as Pedro stepped up to confidently roll the ball home.

Zouma tapped in the fourth from a fine cross from James 11 minutes into the second half.

That meant Lampard could throw in two more debutants, Tino Anjorin and Ian Maatsen, the Blues finishing the night with six academy starlets on the pitch.

So it was fitting that James curled in a fine debut goal and Hudson-Odoi got in on the act after Batshuayi's second to offer yet more hope of a bright future at the club.