That is according to Sky Sports pundit Jamie Carragher.
The Gunners managed to leave Stamford Bridge with a point after a 0-0 draw.
Arsene Wenger was without playmaker Mesut Ozil due to a minor knee injury picked up in training this week.
While the boss chose to leave Sanchez on the substitute bench again as he rebuilds his fitness.
The star duo last started a game together when Arsenal were hammered 4-0 by Liverpool at Anfield.
But speaking at half-time, Liverpool legend Carragher said Danny Welbeck and Alex Iwobi had put in a better shift defensively than the two absentees.
“A proper, disciplined, away performance,” he said on Sky Sports.
“It’s about time. A big thing we mentioned is the midfield, talking about Ramsey and Xhaka, but a big difference is there is no Ozil and no Sanchez.
“Yes, maybe they’re better than these two going forward, but these two in Iwobi and Welbeck have been so disciplined.
“They’ve done their job defensively as a tight midfield, stopping Chelsea going through the middle and forcing them wide to the wing-backs.
“They haven’t been able to get Pedro or Willian on the ball.
“That may change in the second half if (Eden) Hazard comes on.
“There’s more space in there as teams tire.
“But I think the work of Iwobi and Welbeck has been fundamental of this first-half performance.”
It is the first time Arsenal have taken any points away from Stamford Bridge since 2011.
