The side which also contained former Sky Blues Clayton Ince and Stern John who appeared as a 73rd minute substitute, needed only a drew to make the CONCACAF Finals of World Cup Qualifying but turned up the heat in the second half to score three times through Kenwyne Jones, Dwight Yorke and Keon Daniel.
Whilst Birchall was at the Hasley Crawford Stadium, Port Vale had made contact with the Sky Blues about a possible return to the Potteries for the 24 year old who is being allowed to leave Coventry by manager Chris Coleman and apart from pre-season, has not featured in a match since the latest City boss took charge.
Port Vale Chairman Bill Bratt told The Sentinenel:"Chris is in our remit, so when he comes back from playing for Trinidad and Tobago, we will follow it up."