Albion smashed their transfer record as they pulled off a potential £12m deadline-night double-deal for Stephane Sessegnon and Victor Anichebe.
Sunderland forward Sessegnon became the Baggies’ new record signing with a £5.5m switch from Wearside but Anichebe could break the record again with his move from Everton set to eventually hit £6m.
The Baggies went on a final-day spending spree after slumping to the foot of the Premier League and finally offloaded want-away striker Peter Odemwingie to Cardiff for an initial £2.5m.
But head coach Steve Clarke missed out on a new loan deal for fans’ favourite Romelu Lukaku and faces a tricky meeting with former record signing Shane Long next week after allowing the Ireland striker to speak to Hull over a £5m switch, only to pull the plug late on.
The Baggies confirmed the signing of Sessegnon at around 10.30pm with the down-payment believed to be £5.5m with the fee potentially rising to £6m.
And they were then involved in a tense late-night tug of war with Everton for Lukaku after Chelsea boss Jose Mourinho performed a last-minute U-turn and sanctioned a loan move for the 20-year-old.
Lukaku eventually moved to Goodison Park but the battle delayed the signing of 25-year-old Anichebe and Albion then had to wait to ensure the paperwork had been received in time.
The Baggies had earlier agreed a £5m fee with Hull for Long, who has been unable to agree a new contract at The Hawthorns.
The striker flew from the Ireland camp to Hull for talks and a medical and looked set to move but the delay on the Anichebe signing meant Clarke was unable to sanction a deal.
Odemwingie agreed personal terms and passed a medical yesterday but legal wrangling meant that deal – which Albion say could reach almost £4m – was not announced until after 11pm.
Albion had earlier confirmed the loan signing of Marseille midfielder Morgan Amalfitano and a short-term deal for keeper Lee Camp.