Trusty ally Laurens will bid to give the former jump jockey the perfect start to the meeting on Tuesday, by claiming the sixth top-level victory of her career in the Queen Anne Stakes.
Despite the Karl Burke-trained filly having to settle for second best on her return in the Lockinge at Newbury, the 37-year-old rider feels she will prove tough to beat on this occasion.
He said: "I worked her on Wednesday morning and she seemed in good nick. She has come out of the Lockinge really well. Karl made no secret of it, that his horses weren't running great, but to be fair she felt good to me.
"She went through the early part of the race nicely. She travelled and was enthusiastic and she just got a little bit tired, which is understandable.
"If she was a little bit off-colour that day and she isn't come Tuesday, then I will be in for a good spin. Whatever beats her will have to shape very smartly. I'm pretty sure my filly will improve a good deal from the Lockinge to now."
It will not be the first time Laurens has appeared at the Berkshire track, having finished down the field in the Queen Elizabeth II Stakes on Champions Day - but that is an effort McDonald believes can be forgiven.
He added: "With her running style, Ascot probably wouldn't be ideal for her.
"She is an enthusiastic filly that likes to get on with it and wears her heart on her sleeve, and the last furlong you are there to be shot at from something coming off the pace.
"She had a tough season last year and every time she ran, she was in a battle. She never coasted up on any day and I think that is her racing style.
"It looked like she was going to win the Sun Chariot comfortably, but then she had a ding-dong with Happily in the latter stages.
"She has bounced back and proved in the Lockinge that she has trained on and is still enthusiastic and wants to do the job."
This season has seen McDonald forge another successful partnership, with the James Tate-trained Invincible Army, who is set for the Diamond Jubilee on Saturday after winning the Duke of York Stakes last time out.
He said: "He was impressive at Doncaster, but he was even more impressive at York. He relaxed so nicely into the race. He showed a good turn of foot and he put it to bed in three or four strides - and he wasn't stopping. Ascot will suit his running style.
"I've been lucky in that I've got on the horse at the right time and you draw confidence that he is the horse that looks like he can go forward again.
"Touch wood, his mind is so good at the moment that the occasion shouldn't bother him, so he can conserve his energy throughout the day to burn at the furlong pole."
Receiving the chance to partner two genuine contenders on such a stage may be too much to handle for some - but for McDonald, who has yet to ride a winner at the meeting, it is a challenge he is looking forward to taking up.
He said: "To go there in two Group One races with realistic chances is great, as there is nothing worse than going to a big meeting to make up the numbers.
"I've never had a short price or single-figure horse going into the meeting, so fingers crossed we can get one on the board.
"No matter whether you are riding horses, playing football or boxing for the heavyweight title, sports people get nervous - it is about how you handle it, and I am definitely excited and looking forward to it."
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