The Gunners are now placed 12th in the English Premier League table with seven points in five matches and are seeking to break into the top half of the standing after the clash at the Emirates Stadium.
The Nigeria global was handed his first Premier League start of the season at Stamford Bridge last weekend.
Barry has never been much of a creative force, even in his heyday, but the 36-year-old nearly ushered his side into a shock lead when his sumptuous pass sent Jay Rodriguez into the Arsenal area.
The clash between Arsenal and West Bromwich Albion at the Emirates this evening saw Nacho Monreal produce an incredible goal-saving clearance during the first-half.
GETTYJack Wilshere's Gunners career has been disrupted by injuries
However, the visitors were denied a penalty early on though when Jay Rodriguez appeared to be brought down by defender Shkodran Mustafi just eight minutes in.
John Giles of course had a more basic term for that kind of dynamic: "sunshine boys", the players who couldn't get enough of the ball when things were going well, but were nowhere near so assertive when they weren't.
Jonny Evans conceded a free-kick right outside the area with a foul on Mohamed Elneny and Sanchez stepped up to curl the set-piece goalwards. It would be a blow to Arsenal boss Arsene Wenger seeing another major star leave for one of the North London clubs rivals.
But Albion immediately raced down the other end and should have equalised.
And to rub further salt in the wound, Madley didn't hesitate in awarding Arsenal a penalty in the second half when Aaron Ramsey took a tumble from Allan Nyrom.
Madley pointed to the spot and Lacazette clinically dispatched the penalty.