Sissoko is set to clinch a move from Newcastle United, SkySports report, beating Everton to a deal.
Everton had appeared favourites to sign the Frenchman just hours earlier, before Tottenham matched their bid and tempted him to sign with the North London club, with the deal set to be confirmed imminently.
Merson said: "I like Everton. He's not going to win the Champions League (at Tottenham). Fingers crossed it doesn't go through."
The former Arsenal midfielder may be disappointed however, with the £30 million transfer close to being finalised.
An announcement over Sissoko is expected at any moment, with the midfielder posting a message on Twitter - with a Tottenham shirt, declaring he has signed a five year deal.