Jaime Alguersuari joined the expected casualties in the opening phase of qualifying for the Monaco Grand Prix after clipping his Toro Rosso's front wing in his efforts to make the top 17 times.

The Spaniard, along with STR team-mate Sebastien Buemi, had shown top ten pace in the morning practice session but, while Buemi escaped the drop zone with a late flying lap, Alguersuari only served to run into the back of a Sauber at La Rascasse. The damage was enough to deny him an improvement in time and saw the under-fire youngster restricted to the pits as the session ticked down to a conclusion.

Alguersuari, who may also face a penalty for the clash, joins the six cars already anticipated to miss the cut, especially after Mercedes was able to rebuild Nico Rosberg's shattered car between sessions. Tonio Liuzzi was not so fortunate, with Hispania electing not to even try to make the deadline, and team-mate Karthikeyan also remains in danger of not making the grid on Sunday after failing to set a lap time.

With Paul di Resta making his own late escape from the bottom seven, Heikki Kovalainen was unable to repeat his Barcelona heroics, and missed the cut by half a second. The Finn heads Team Lotus team-mate Jarno Trulli in 18th and 19th, while Virgin colleagues Timo Glock and Jerome d'Ambrosio sit behind Alguersuari on what could be the final row of the grid.

McLaren enjoyed a 1-2 at the sharp end of the timesheets, with Lewis Hamilton heading Jenson Button. Sebastian Vettel was third fastest, with an impressive Rosberg making the top five despite not having completed a flying lap since Thursday.