McMullan and Scotland face Australia in their final group match but are brimming with confidence after an impressive start to the tournament.
McMullen said, “We are confident about the match against Australia and will always try to raise our standards. This is the plan going forward.”
Scotland's run chase got off to a good start, with George Munsey making 41 before he was caught by Shakil Ahmed off Mehran Khan, while Michael Jones added 16.
McMullen then took charge of the match and finished the match in partnership with Matthew Cross, who remained unbeaten on 15 runs off eight balls including two huge sixes.
Meanwhile, Oman captain Aqib Ilyas rued his side's failure to post a more competitive total and missing opportunities in Scotland's innings after winning the toss and electing to bat first at the Sir Vivian Richards Stadium in North Sound.
“175 would have been a good score but we played too many dot balls on a flat pitch,” Aaqib said. “We need to improve our batting. 150 was a par score but we missed too many chances.
“If you take a catch it puts pressure on the other team. This is cricket, sometimes you are on top and sometimes you are down.”