Horner: Driver Decision on Monday

Liuzzi, the reigning F3000 champion, was signed on a joint deal with Christian Klien to share the second seat alongside lead driver David Coulthard in the team's debut season this year.

Klien was handed the seat for the first three races and claimed a total of three points before Liuzzi stepped in at the San Marino Grand Prix and scored a point on his debut.

Both drivers have shown impressive form so far and Horner said: "The situation is pretty clear. He (Liuzzi) gets three races in line with what Christian got and after Sunday we will take a decision as to who sits in the car next.

"We'll have those facts (to make a decision) by Sunday evening. Christian is champing at the bit to get back in the car and we will make a decision on Monday morning."

Horner backed Liuzzi, who raced for his Arden team in Formula 3000 last year, despite seeing the Italian make a mistake at the last race in Barcelona, but admitted it will be tough for him to impress in Monte Carlo.

He has some track knowledge after winning here last year in F3000 but Horner said: "This is a tough animal around here, going into your third Grand Prix it's a tough circuit but so far we are pleased with the job that he's done.

"He had a very good debut in Imola, he drove a very strong race when the car wasn't comparatively performing as well as it had done previously and for a debut race he drove very strongly and ultimately got a point out of it.

"In Barcelona he had a lot of fuel in the car and made a mistake. Hopefully he will have learnt from that - hopefully he has. I think for a rookie he's done an excellent job so far. Obviously the mistake in Barcelona was unfortunate.

"Christian did very well in is three races before Tonio came in so we have a very healthy situation, with healthy competition."