The Boro boss was “delighted” with the majority of his team’s display but left frustrated by the Baggies scoring an equaliser five minutes after half-time through John Swift.
Isaiah Jones had put Middlesbrough in front in the 10th minute during an opening period when the home side looked much better than their opponents.
But a failure to make the most of those good opportunities provided a reminder to Wilder that there needs to be further movement on the transfer front – particularly with Marcus Tavernier on the verge of a move to Bournemouth.
Wilder, who revealed he wants five more new signings before the window closes, said: “The performance was excellent.
“The 10 to 15 minutes after half-time opened the door for them and it became a game of basketball. We lost shape and structure a bit.
“But the things that have gone off in the week, to where West Brom are and we are, is a different ball park at the moment. It won’t be when the window is shut. This is how it is at the moment.
“There shouldn’t have been a West Brom comeback because we should have put it away in the first half. We missed chances, the final ball wasn’t right at times, and I would be a touch critical in terms of going for the jugular. We had them on the ropes.”
Middlesbrough: Steffen, Dijksteel, Lenihan, Bola, Jones, Crooks, Howson, McGree, Giles, Watmore (Forss 63), Akpom (Coburn 63). Unused substitutes: Fry, Smith, Boyd-Munce, Roberts, Hackney.
West Brom: Button, Furlong, Ajayi, O’Shea, Townsend, Molumby (Mowatt 90), Livermore, Wallace, Swift, Phillips (Diangana 68), Ahearne-Grant (Dike 78). Unused substitutes: Bartley, Reach, Palmer, Gardner-Hickman.
Referee: T Harrington (Cleveland).