Tenebrism produced a brilliant performance in coming from virtually last to first to win the Juddmonte Cheveley Park Stakes at Newmarket.
Aidan O'Brien's charge had just one previous run under her belt, winning a Naas maiden back in March, but she shrugged off her 181-day absence in some style with a power-packed finished.
Flotus led them up the stands side in the six-furlong contest, setting a sound pace in front as Ryan Moore was out the back on 14-1 shot Tenebrism.
It looked as though Simon and Ed Crisford's Flotus had the measure of her rivals with a furlong to run, as favourite Sacred Bridge and her main market rivals Sandrine and Zain Claudette were all making little impact on the leader.
However, Tenebrism was responding in kind for Moore and found an extra gear to sweep by Flotus and win going away by a length.
Sandrine kept on for third, beaten a further three lengths in the Group One heat.
Tenebrism, who boasts an exceptional pedigree as a daughter of Caravaggio out of top miler Immortal Verse, is 8-1 for the 1000 Guineas with both Betfair and Coral.