Chelsea and Tottenham Hotspur could become locked in a bidding war for Real Sociedad winger Antoine Griezmann after Spurs had an initial £15m bid rejected.
Spurs have monitored the 23-year-old over the summer and hoped to strike early to land the France international.
But La Liga club Sociedad are holding out for a fee believed to be around £25m, which would trigger a release clause in the player's contract.
But after the north London side's offer was rebuffed, Chelsea could enter the fray with moneybags Monaco to secure Griezmann, reports the Daily Mail.
Spurs have had a quiet transfer window so far after splurging £90m last summer but have been linked with a double bid for Southampton pair Morgan Schneiderlin and Jay Rodriguez in a £35m swoop.
But Saints boss Ronald Koeman is fighting to keep hold of the prized duo after already losing Adam Lallana and Ricky Lambert to Liverpool and left-back Luke Shaw to Manchester United.
Griezmann impressed at the World Cup after being thrown into first-team action when Bayern Munich's winger Frank Ribery failed to recover from back injury in time for the tournament.
He was a constant presence on the left flank in Didier Deschamps' line-up as Les Blues were eventually knocked out of the competition by eventual winners Germany at the quarter-final stage.
Tottenham seem able to offer Griezmann a better chance of first team football after Jose Mourinho added Cesc Fabregas, Diego Costa and Filipe Luis to the ranks of his west London side.
The imminent departure of Gylfi Sigurdsson to Swansea also leaves Tottenham boss Mauricio Pochettino with a vacant position in his midfield roster.