McCarthy (Porto) is booked.
Ruled offside, the striker kicks the ball away to waste time and is booked.

Costinha (Porto) scores!
Howard saves McCarthy's curling free-kick, but he cannot hold the ball, and the following-up Costinha lashes the ball in to turn the game in dramatic fashion.

Solskjær (in) - Ronaldo (out) (Man. United)
The Norwegian, who turned 30 in February, is on for his first Champions League appearance since Matchday 1. His absence was due to injury, and his arrival is for the same reason, with Ronaldo taken off on a stretcher.

R. Fernandes (in) - Alenichev (out) (Porto)
A final throw of the dice for Porto, with a left-sided set-piece specialist on.

Ronaldo (in) - D. Fletcher (out) (Man. United)
The 19-year-old, named after Ronald Reagan, slots in on the right of midfield.

Maniche (Porto) is booked.
A boot brought down on Scholes' shin, and a card for Maniche, who has already served a suspension for two bookings in the group stage.

Jankauskas (in) - Carlos Alberto (out) (Porto)
A straight swap up front.

Scholes (Man. United) is booked.
The foul earns the English international a booking that leaves him suspended for United's next European match - whether in the first leg of the quarter-final, or if they go out tonight, their opening game next season.

Saha (in) - Djemba-Djemba (out) (Man. United)
It seems Saha and Giggs will both play just behind Van Nistelrooij, with the Frenchman on the right, and Scholes back in midfield.

The referee blows for half-time.

Pedro Emanuel (in) - Jorge Costa (out) (Porto)
Pedro Emanuel came on as a 71st-minute substitute when Porto beat Celtic FC in last season's UEFA Cup final, and is now filling in at centre-back for the injured captain.

Scholes (Man. United) scores!
Suddenly, the breakthrough. Giggs sends O'Shea clear on the left, and the defender cuts back superbly and sends in a perfect hanging cross for Scholes to leap and head in from close range.

Costinha (Porto) is booked.
A foul on Van Nistelrooij in the move that continues to allow United to win a corner, collected by Vítor Baía.

P. Neville (Man. United) is booked.
A trip earns Phil Neville his first booking of this season's Champions League.