It was only a matter of time until Jason Green made a real impact on this season's Whitney Cup and on Saturday his brilliant century gave Macquarie the upper hand in their clash with CYMS.

Green held the innings together after coming in with the score at 2-11 in the fifth over and he didn't give the Cougars a chance, finishing unbeaten on 168 in his side's total of 7-312 at Lady Cutler 2.

Last season's Whitney Cup player of the season hit 24 fours and two sixes in his knock and Macquarie captain Keiran Brien admitted his side was a different outfit when the veteran left-hander fired.

"I was very happy with him, without him we're struggling," he said.

"He batted really well, he did his thing and what a few of us others couldn't.

"Someone had to stand up, we needed others to go with him but it's what we've got to work on, if you get one bloke with a good score then hopefully you can get to that 300."

Stand-in CYMS captain Harry Brennan won the toss and elected to bowl. That looked a wise decision when Ben Strachan struck twice in two balls in his third over, but then Green and Ed Haylock combined for a 122-run partnership which got the Blues back on track.

Haylock rode his luck as CYMS' catching woes haunted them again but he was eventually trapped in front by leg spinner Ryan Medley for 49.

The Cougars bowlers continued to chip away through the middle with Dale O'Donnell bowling a perfect spell with an old ball to take four wickets and keep the Blues' score in check.

But while Green remained at the crease Macquarie were always capable of piling the runs on and despite battling back pain he combined with fellow veteran Justin Gavin (44) for a 96-run partnership to help the score past 300.

O'Donnell was CYMS' best and finished with 4-84 while Strachan toiled all day and took 2-77 from 25 overs.

Brien, who admitted he would have batted if he won the toss anyway, said he was pleased to see his team pass 300 against the Cougars for the second time this season but admitted his side would have to bowl and field well next week on the fast Lady Cutler outfield.

"I could see what Harry (Brennan) was doing at the toss because CYMS are definitely a better bowling side than batting with 'Strachany' and the like so we expected that," he said.

"We're confident, we've got the bowlers and from what we did last game against Newtown, we bowled them out for 200, so we're feeling very confident with our bowlers and we've got Joey (Haylock) and 'Pagey' (Ben Page) back too so we're happy defending that but this field is lightning so we'll have to bowl well and defend it and hope for a good result."