Warwickshire County Cricket Club piled on the runs on the opening day of their County Championship game with Durham at Edgbaston.
Warwicks won the toss and opted to bat and it proved a good decision after a shaky start which saw Varun Chopra out for thirteen and Will Porterfield out for one.
Jon Trott made 42 before being trapped lbw by Onions but after lunch, Ian Westwood and Laurie Evans had a partnership of 106, which ended when Onions had Evans caught by Mustard after making 45.
A run later and Onions had his fourth wicket when he bowled Westwood for 88.
After Tim Ambrose had gone for thirteen, Ricky Clarke and Keith Barker put on 1-3 before Barker was trapped lbw by Rushworth.
Barker and Jeetan Patal came togther and they took Warwicks through to the close of play after 96 overs with Barker 86 not out and Patal fifty not out and Warwicks on 417-7.