Continuity mistake: Peter states that his first match is at 3 PM, but when he goes out onto the court to begin the match we hear him thinking that it is 2 PM.
Continuity mistake: In a couple of close up head shots of Paul Bettany in the final match, the tag in his shirt is visible. In one shot the size of the t-shirt is L (large), in a later shot within the same scene it says M (medium).
Continuity mistake: On the London Eye, Peter and Lizzie are looking at the Houses of Parliament from quite a height, so they've got around ten minutes before they're back on the ground (a "flight" takes around 30 mins). Jake walks up, Peter punches him, then immediately they run off in the hubbub afterwards, suddenly back at ground level.
Continuity mistake: When Peter goes out to play Ajay Bhatt in his first round match, we hear him thinking "It all ends here, at 2pm on Court 17". Later, after Peter has won the first point the camera pans back over him and the scoreboard, which reads "Court No. 8".
Continuity mistake: When Lizzie and Peter are talking in the sushi restaurant, Lizzie's hair moves positions between shots. In shots of her talking, her hair is in front of her shoulder. In shots of Peter talking, you can still see Lizzie and her hair is behind her shoulder.
Continuity mistake: In the final tennis scene the shadows change direction with practically every shot.
Continuity mistake: When Peter is going up to Lizzie's room with the fish and chips, he has cut himself shaving. The piece of paper he has stuck to his face starts off on the corner of his lip and then jumps down and left.
Continuity mistake: Peter and Lizzie run away from a party after getting off of the London Eye. When they get on Peter's car, it doesn't have a rearview mirror. When they leave the city, a rearview mirror appears.
Continuity mistake: When Peter stays behind to work on his serve, he has 5 ball tubes and 2 beer cans in his hand (which he is using for target practice). The number of tubes on the court and the position of them changes countless times while he is serving with Lizzie. (00:10:35 - 00:12:10)
Continuity mistake: In the final match scene when the rain comes Peter is laying on the ground. He turns onto his back and his shirt is very nearly clean. Then as he sits up his valet says "What are you doing, Lad? Get in here!" Peter's shirt has a large mud stain on it. (01:13:05)
Continuity mistake: When the exterior of Peter's flat is first seen, there is scaffolding outside the front door. The following morning when Lizzie's father comes looking for her, the shot on the TV of the exterior shows no scaffolding. (00:36:30 - 00:43:15)
Continuity mistake: When Lizzie and Peter escape the Slazenger party and Peter starts to drive, there is no traffic behind them. But when Lizzie kisses him, distracting him from the road, there is suddenly a big red bus behind the car.
Continuity mistake: When Lizzie's father comes looking for her, he walks up two flights of stairs to get to Peter's door. When Peter opens the door, you can see the number 4 on the door. (00:43:10 - 00:45:30)
Answer: "This Years Love" by David Gray (from his White Ladder album).