After two wins in their opening three Blast matches, the Falcons have suffered bruising defeats in their past two encounters, conceding 219 to Lancashire to go down by 17 runs at Old Trafford and then allowing Notts Outlaws to rattle up 182 for three in 17 overs to win by seven wickets on Friday.
The South African was not at all happy with the performance of his team, and particularly his bowlers.
And he has made it clear he expects to see a reaction at Wantage Road, even though his team is coming up against a free-scoring Steelbacks side that has hammered an aggregate 450 for five in their 40 overs at home so far this season!
On the home defeat to Outlaws, Arthur said: "I am incredibly disappointed, the execution in our bowling was nowhere near.
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"We have got a lot of work to do in that discipline in what is now now a massive week for us.
"We will perhaps be looking at a change of tactics, and perhaps looking at other options, and we also need to make sure that we execute our plans better than we did.
"I hate losing, we hate losing, and we have had three losses so far - that is not good enough from us to be brutally honest.
"This is a big week for us, we have nine games to go and we are probably going to need to win five or six of those to qualify.
"We take on Northants, Leicestershire and Worcestershire and they are games where I expect us to get out there and perform."
Derbyshire have named a 14-man squad for the trip to Northampton.
Their form player is Leus du Plooy who has hit half-centuries in the past two matches.
Derbyshire squad: Shan Masood (c), Luis Reece, Harry Came, Leus du Plooy, Wayne Madsen, Brooke Guest (wk), Mattie McKiernan, Anuj Dal, Alex Hughes, Alex Thomson, Hayden Kerr, Sam Conners, Mark Watt, George Scrimshaw