Sam Robson and Gary Ballance shone with the bat before Tymal Mills took 3-6 to put the England Performance Programme in the box-seat with a day remaining of their match against a Western Australia Second XI at the James Oval in Perth.
Resuming on 34 for one, Robson and Ballance put on a mammoth 193-run partnership for the second wicket as the tourists dominated the second day.
The former compiled an unbeaten 108 - his second century in successive games on tour - and the latter a fine 89 as he pushed his claims for a Test debut in Perth.
The EPP declared when Ballance's 126-ball innings came to an end, which gave the bowlers a chance to make inroads into the Western Australia batsmen - an invitation Mills accepted with relish.
Bowling quickly and extracting bounce, he took three wickets in eight balls as the hosts slumped to 14 for four with Chris Jordan taking the other wicket to fall.
Moeen Ali struck to further reduce WA to 32 for five but the EPP bowlers were kept at bay by an 89-run stand between John Rogers and Tim Armstrong.
James Vince brought that to an end when he bowled Rogers for 45 and the home side eventually closed on 167 for six - a lead of 266.