Olivier Giroud dragged Arsenal back to winning ways as his 86th-minute header snatched a 1-0 win over West Brom at Emirates Stadium.
Tony Pulis' visitors held Arsene Wenger's men at arm's length during a dour first period on Monday but were indebted to goalkeeper Ben Foster after the interval.
The 33-year-old marked a fresh contract extension with West Brom by making impressive stops from Giroud, Alex Iwobi and Alexis Sanchez, while the latter also rattled the post.
It meant Arsenal left it late to maintain their record of scoring in each of their 21 Premier League encounters with Albion - who ultimately rued Claudio Yacob failing to punish Petr Cech's misjudgement at a 70th-minute corner - as Giroud grappled with Gareth McAuley to steer a fine header over Foster from Mesut Ozil's searching cross.