Chelsea outclassed a tired-looking Arsenal side throughout this preseason friendly and had taken the lead through Willian in the 40th minute, with Batshuayi getting the second less than two minutes later.
Arsenal may blame tired legs for this defeat as it was the last of four games they have played on a two-week tour of Australia and China, while Chelsea were playing their first match of their preseason trip to Asia.
Chelsea manager Antonio Conte also played arguably his strongest possible lineup, while Arsene Wenger started academy prospects Cohen Bramall and Ainsley Maitland-Niles and made mass changes at half-time.
They could easily have made it a bigger rout were it not for a couple of fine stops from David Ospina, including a double save to deny Willian and Victor Moses when it was still 0-0. Batshuayi then had the ball in the net from the ensuing corner but was waved offside.
Willian soon broke the deadlock, though, as he cut in from the left across the area and fired a low shot past Ospina inside the far post.
The second goal was a near mirror image in reverse, with Batshuayi shooting into the opposite corner with his left foot.
The striker’s second was the highlight of the night, though — a long-range curler that a diving Ospina could not reach.
Conte made it clear in Beijing that Morata will be his first-choice striker after completing his signing from Real Madrid, but Batshuayi showed here that he will do his best to be more than just a backup.
The only negative for Chelsea was Pedro having to come off in the first half, looking dazed and groggy after being sandwiched between Maitland-Niles and Ospina when trying to get on the end of a long ball over the top.
For Arsenal, it was a disappointing ending to their tour, which had seen them earn two wins in Sydney and then beat Bayern Munich on penalties in Shanghai in sweltering heat on Wednesday.
Olivier Giroud was also nearly prevented from coming on as a half-time substitute after an admin error saw the French striker left off the official teamsheet, but he was eventually allowed to play after several minutes of heated discussion between Wenger and the officials.
The Gunners were heading straight to the airport to fly home after the game, while Chelsea will continue to Singapore for games against Bayern and AC Milan.
The London sides, who also played each other in the FA Cup final in May, will square off again in the Community Shield at Wembley in two weeks.