The benchmark index hit an all-time high of 338.0 points last Friday, boosted by four weeks of consecutive gains.
However, the STOXX closed at around 333.2 on Friday afternoon — 1.2 percent lower on the day and 1.4 percent down on the week. This followed sharp losses at the start of week, caused by the West-versus-Russia confrontation over Ukraine, and profit-taking on Thursday and early Friday following ECB President Mario Draghi's news conference — which was slightly more hawkish than expected.
(Read more: Ukraine's PM: No concessions on Crimea)
"The profit-taking was more about Mario Draghi than Ukraine," Brenda Kelly of IG Group in Dublin told CNBC.
"We saw a little bit of hawkishness from Mario Draghi – we were mostly expecting to see a degree of dovishness, and some element of non-sterilization (of the ECB's funds that it has spent on purchasing government bonds)."
She forecast the STOXX would continue to target the 338.0 level, and could rise still higher.
"It's certainly possible. What is most likely to happen in the immediate near-term is that we will see a bout of profit-taking… in case the crisis in Ukraine escalates," Kelly said.
Ishaq Siddiqi, market strategist at ETX Capital, predicted that European stocks would rebound come Monday, but that prices would then drift.
He said European markets looked "pretty exhausted," particularly the German Dax and to a lesser extent, the U.K. FTSE 100.