Crystal Palace were beaten 3-1 by West Ham United on Saturday.
West Ham beat Palace 3-1 at the weekend, and although Sakho did not get on the scoresheet, Delaney was still impressed by the striker's work rate.
"The boy they have up-front, Sakho, is relentless in his running," Delaney said. "He runs down the sides and he stretches you, which creates the spaces for [Manuel] Lanzini and [Dimitri] Payet. Those were both pretty good yesterday.
"I was impressed by Lanzini yesterday, I didn't even know where he came from [prior to his move to West Ham] but he was good."
Delaney was forced to watch Palace's defeat from the stands, as he is currently out injured.
He may have been grateful not to have to mark Sakho, though, as the Senegalese forward is a defender's nightmare.
Sakho has pace and power in abundance, and his boundless energy means that he is a real asset for Slaven Bilic's men.
Although Sakho may not have scored as many goals as he would have desired so far this season, he will hope to continue to impress, as the Hammers look to protect their place in the top-four of the Premier League table.