Derek McInnes saw his Aberdeen side fall to a 3-0 defeat to Motherwell in the Scottish Cup semi-final and admitted it opened his eyes to changes he'll have to make to his squad.

The Dons saw their mistakes punished by the Steelmen in a match where they never really looked like progressing to the final and McInnes said part of the reason was not being able to replace key players.

A two-minute burst in the first half saw Curtis Main and Ryan Bowman punish errors, with Main scoring hi second on the counter in the second half to sink Aberdeen.

McInnes pointed to what he felt was a missed handball in the lead-up to the opening goal but had no other complaints, feeling the side on display wasn't up to the standards he wanted.

Captain Graeme Shinnie was suspended, as were Kenny McLean and Shay Logan. Wingers Gary Mackay-Steven and Niall McGinn weren't fit enough to start after injury and McInnes had to reshuffle his squad.

"I said I wouldn't use the players that were suspended as an excuse but it's clear that we struggled to replace like for like," he said. "I don't take responsibility in terms of today's performance because as a manager you can't legislate for mistakes.

"Where we I take responsibility is the recruitment. Today smacked me between the eyes that the strength of the squad wasn't good enough.

"The decisions we've made in both windows have come back to bite us.

"There's going to be a big turnaround in the summer. We've got a few loan players and have already lost Kenny (McLean, who will return to parent club Norwich) so there will be a big recruitment again.

"I didn't play the team I wanted to play today, I played the team that needed to be played and unfortunately it wasn't good enough."