The phrase "a performance which was" is correct and usable in written English.
It can be used to describe a specific performance in the past, often in a context where you are providing details or opinions about it.
Example: "The concert was a performance which was both captivating and memorable, leaving the audience in awe."
Alternatives: "a performance that was" or "a performance which had been".
Despite the frantic conclusion, Wenger was impressed by a performance which was, for 85 minutes, professional and focused.
Saturday's goalless draw has effectively extinguished Welsh hopes of competing in the Euro 2008 finals but, after a performance which was arguably their best of the whole qualifying campaign, John Toshack was understandably more eager to respond to Savage's remarks.
One of Olivero's greatest triumphs as Adriana came in Naples in 1959, when she replaced Tebaldi at the last moment and took part in a performance which was recorded and has remained one of the jewels of the so-called "pirate" recording repertory.
Labour lost a net 18 council seats at last month's local elections, and edged ahead of the Conservatives on share of the vote – a performance which was regarded with relief by some in Corbyn's inner circle, but which raised questions about whether the party is on track to win a general election in 2020.
The Russian composer debuted The Rite of Spring in Paris in 1913, a performance which was reported to have sparked a riot in the theatre.
"In the Champions League round-of-16 against Atletico Madrid he produced a performance which was viewed as one of the worst ever and it was the final straw.
But an Oscar for Samuel L Jackson in Pulp Fiction would honour a performance which is just iconic, part of movie history.
"The high ceilings give the room an amazing natural reverb and that can often be quite forgiving and flattering to a performance, which is really useful while you're figuring out arrangements.
The youngster registered his first international goal and picked up the man of the match award in England's victory over France on Tuesday night, a performance which is thought to have accelerated Tottenham's plans to open talks.
"Questions will be raised if I can't come forward this year with a performance which is the gold, or pushing for the gold at the very least".
Roughly, optimized means that the used learning rate η ∗ yields a performance which is better that when using 1.5 η ∗ or η ∗ / 1.5.
