Pyke says poor skills cruelled the Crows in their shock 14-point AFL defeat last night.
Adelaide cling to top spot ahead of weekend games but they have lost four of their past seven fixtures.
Pyke rejected any thought of complacency as a factor, or the bye – the Crows and Hawthorn were both resuming after a week off.
“I am not going down the path of the bye being the reason,” Pyke said.
“But it was a very disappointing night all round… it was quite off.
“Our execution tonight was miles off the level [required].”
Pyke said Adelaide’s slack skills were uncharacteristic in a loss which is a setback to the club’s bid to consolidate at the top.
“It’s not ideal,” Pyke said.
“We obviously set ourselves for the second half of the season and this is a poor way to start it.
“We have got to regroup pretty quickly… and clearly play and perform better than we did.”
But Pyke ruled out swinging huge selection changes in response to the defeat.
“We will keep faith with the group. The group has got us to this point now,” he said.
“The reality is in this competition, if you don’t bring fundamentals in a really strong sense and don’t play those for four quarters, you’re going to be in trouble.”
Ball magnet Tom Mitchell collected 38 disposals and kicked a clutch goal as the Hawks won 14.12 (96) to 12.10 (82).
Emerging star Ryan Burton, veteran Shaun Burgoyne, Paul Puopolo, ex-Crow Ricky Henderson and Tim O’Brien kicked two goals each for the unfancied visitors.
Adelaide (nine wins, four losses) blew a chance to consolidate at the top of the table – they led in the last quarter but couldn’t close the deal.
Instead, South Australian recruit Puopolo, Adelaide discard Henderson and onetime Port Adelaide star Burgoyne kicked the last goals of the game for a stirring win for the visitors.
“It wasn’t a pretty game… we needed to compete really well,” Hawks coach Alastair Clarkson said.
“We did that for the best part of the night which was really pleasing.”
Henderson (30 disposals) was prominent in Hawthorn’s fifth win, with ball-winner Mitchell’s midfield colleagues Burgoyne (26 disposals) and Liam Shiels (21 touches) also busy.
They helped stifle a Crows side overly reliant on brothers Matt and Brad Crouch, who had 64 disposals between them.
Rory Atkins (28 possessions), link-man Tom Lynch and Rory Laird (28 disposals) battled gamely while Josh Jenkins kicked three goals.
But the Crows were on the back foot from the start – Hawk stalwarts Burgoyne and Jarryd Roughead each goaled inside four minutes.
Adelaide, before a 45,312-strong home crowd, drew level by quarter-time – 4.2 apiece – and their vaunted attack found fluency in the second stanza with keys Taylor Walker and Jenkins kicking two majors each.
Their scoring helped Adelaide craft an 18-point halftime advantage and the competition pacesetters appeared in control.
But the plucky Hawks rallied after the break, booting three consecutive goals – the last two uplifting on-the-run efforts by Burton – giving the visitors a two-point lead.
Adelaide’s Hugh Greenwood replied as the Crows went five points ahead at three-quarter time – the former NBL player turning in his best AFL game to date.
But Henderson – in his 100th AFL game and against his former club – and the influential Mitchell goaled before Andy Otten struck back for the Crows.
After a tense scrap of behinds, Hawthorn veteran Puopolo converted for a seven-point break before Henderson and Burgoyne struck the sealers.