Cheltenham assistant boss Neil Howarth admitted his side were left frustrated as they threw away a lead to draw 1-1 with Northampton.Newly-appointed Cobblers boss Chris Wilder saw his side fall behind to a Jamie Cureton tap-in following a glaring error from goalkeeper Matt Duke with less than a minute on the clock. But Matty Blair's 75th-minute equaliser ensured Wilder had something to smile about. However, Robins assistant Howarth said: "There was frustration and anger, this has happened too many times and it is another mistake that has cost us picking up a much-deserved victory. "We created the most chances over the game but we have to be killing teams off because the opposition will have an opportunity to get something out of the game. "We weren't set up right for their goal and we should have done a lot better. "I thought our performance wasn't too bad, we were passing the ball around quite nicely at times, but the conditions were incredibly bad."