Hours after striker Steven Fletcher put pen to paper on a four-year deal at the Stadium of Light, Martin O'Neill succeeded in signing out-of-favor Manchester City winger Adam Johnson to a contract of equal length.
Johnson's transfer is believed to be in the region of £10 million—rising to £15 million after certain add-ons.
Coupled with the £12 million O'Neill spent on Fletcher, Johnson's arrival marks a definite show of the manager's ambition for the season.
"Adding quality players to the squad has been our main aim this summer, and Adam certainly fits that bill," O'Neill told the club's official website.
The day's frenzied action makes it four players brought in to Wearside this summer, with Fletcher and Johnson joining free transfers Carlos Cuellar and Louis Saha.
The latter duo featured in the Black Cats' season opener against Arsenal last weekend, which ended in an impressive 0-0 draw.
Defensive solidity was the calling card of that encounter, but given the attacking prowess inherent in Fletcher and Johnson, there's every reason to believe Sunderland can showcase some impressive football this season.