(and 5/99 shortly thereafter), Jonassen formed two key partnerships—a 77-run sixth-wicket stand with Alyssa Healy and a 68-run ninth-wicket stand with Kristen Beams—to take the tourists to 8/268 at stumps. Resuming the second day on a score of 95, she could only manage four more runs before being dismissed lbw by Katherine Brunt on 99 off 197 balls and thus falling agonisingly short of a debut Test century. In the second innings of the match, Jonassen took her first Test wicket by bowling Georgia Elwiss for 17. She recorded another half-century in the third innings, this time making 54 off 72 to expedite the state of play and ensure Australia wrapped up victory on the fourth and final day. In the second T20I of the 2015 Women's Ashes at the County Ground in Hove, Jonassen was her team's equal-top scorer, making 21 runs off 16 balls. She also took 1/15 from three overs with the ball and two catches in the field, helping Australia defeat England by 20 runs and clinch a series victory. 2016–18: Knee injury, third world championship On 22 February 2016, Jonassen achieved her first five-wicket haul in ODI cricket during a Rose Bowl match at the Bay Oval. She finished with figures of 5/50 from nine overs, helping restrict New Zealand to a total of 9/206 which Australia chased down with 54 balls remaining to win by eight wickets. In the first T20I of the 2017–18 Women's Ashes at North Sydney Oval, Jonassen took 1/14 off three overs in a six-wicket win which saw Australia retain the Ashes. Her only wicket occurred on the second ball of the match, removing England captain Heather Knight via caught behind for a duck. The dismissal was "shrouded in confusion" as Knight was first adjudged out by the officiating umpires, then not out and then out again. The MCC's Laws of Cricket Advisor Jonny Singer later argued that Knight should have been reprieved. Jonassen underwent knee surgery during September 2018 for the fourth time in her career. She made her return to international cricket on 29 October in a T20I against Pakistan at Kinrara Academy Oval. Despite being named in Australia's squad for the 2018 ICC World Twenty20, Jonassen did not play a match throughout the tournament which the team went on to win by defeating England in the final. In a blog post for The Athletes Voice, she described