The chase is on. Atlassian reported its largest-ever quarter for taking share from a major IT service management provider, CEO Mike Cannon-Brookes said on the company's fiscal third-quarter earnings call Thursday, escalating its rivalry with ServiceNow. “This is our largest ever quarter for competitive displacements from a major ITSM provider,” Cannon-Brookes said, without referring to ServiceNow by name. “We're taking share from rivals as customers move away from legacy systems and choose Atlassian for a more modern, AI native and much better value service platform. As I said before, I believe AI is one of the best things that has ever happened to Atlassian.” The wins put ServiceNow under pressure from an established, though sizably smaller, competitor even as it faces a growing threat from the larger Salesforce in its fight to keep those same ITSM customers.…